WorldWideScience

Sample records for atlantic period ca

  1. The Danish fish fauna during the warm Atlantic period (ca. 7000-3900 bc): Forerunner of future changes?

    DEFF Research Database (Denmark)

    Enghoff, I.B.; MacKenzie, Brian; Eg Nielsen, Einar

    2007-01-01

    frequently caught species in the Danish Stone Age sea. These results demonstrate that major changes to the fish fauna near Denmark will occur as climate changes. However, exploitable cod populations can potentially be maintained in waters near Denmark, including the North Sea, but the vulnerability......Vast amounts of fish bone lie preserved in Denmark's soil as remains of prehistoric fishing. Fishing was particularly important during the Atlantic period (ca. 7000-3900 bc, i.e. part of the Mesolithic Stone Age). At this time, sea temperature and salinity were higher in waters around Denmark than...... today. Analyses of more than 100,000 fish bones from various settlements from this period document which fish species were common in coastal Danish waters at this time. This study provides a basis for comparing the fish fauna in the warm Stone Age sea with the tendencies seen and predicted today...

  2. Reinvestigating the "salinity effect" on Atlantic Globigerinoides ruber Mg/Ca ratios

    Science.gov (United States)

    Hertzberg, J. E.; Schmidt, M. W.

    2012-12-01

    Numerous culturing, core-top, and sediment trap studies show that temperature is the primary control on Mg/Ca ratios in foraminiferal calcite, and calibrations of this relationship have been applied successfully to the paleo-record to reconstruct ocean temperatures across a wide range of time periods. In addition, paired Mg/Ca temperatures and δ18Ocalcite measurements on surface dwelling foraminifera are often used to reconstruct past δ18Osw variability, a robust proxy for sea surface salinity. However, a recent study of core-top sediments across an Atlantic meridional transect suggests that salinity might have a stronger control on foraminiferal Mg/Ca ratios than previously thought. By analyzing Mg/Ca ratios and δ18O on the planktonic foraminifera Globigerinoides ruber (white), Arbuszewski et al. [2010] found a 27% increase in G. ruber Mg/Ca ratios per 1 salinity unit increase for seawater salinities above 35. In this study, we use shell weight analyses and SEM images from a subset of the core-tops used in the Arbuszewski et al. [2010] study across a narrow depth range (3197 - 3559 m) to show that G. ruber shells from the equatorial region are highly dissolved compared to those from the gyres, significantly impacting their Mg/Ca-SSTs. Shell weights from the higher-productivity equatorial regions of the Atlantic are on average 20% and 15% lower than those from the oligotrophic North and South Atlantic gyres, respectively. Given the large preservation gradient along the Mid Atlantic Ridge, Arbuszewski et al.'s [2010] application of a single depth-corrected Mg/Ca:SST equation [Dekens et al., 2002] on cores from the subtropical gyres and the equatorial region is not appropriate. When regional differences in preservation are considered, as well as realistic calcification seasons for G. ruber in temperate latitudes, we find a strong correlation between SST and G. ruber Mg/Ca ratios in core-top samples spanning 43°N to 25°S in the Atlantic. When we also consider

  3. North Atlantic Globorotalia inflata coretop Mg/Ca calibrations and temperature reconstructions over Termination I

    Energy Technology Data Exchange (ETDEWEB)

    Farmer, Elizabeth J; Chapman, Mark R; Andrews, Julian E, E-mail: e.farmer@uea.ac.u [University of East Anglia, School of Environmental Sciences, Norwich, NR4 7TJ (United Kingdom)

    2010-03-15

    Mg/Ca ratios from planktonic foraminifera are widely used as an independent proxy for ocean temperature. The choice of calibration is vital for reconstructing meaningful temperatures. We present preliminary results based on a new Mg/Ca-temperature calibration (Mg/Ca = 0.92e{sup 0.039T}) for the thermocline-dwelling foraminifera Globorotalia inflata, derived using a suite of North Atlantic coretops. The downcore Mg/Ca record from core SU90-03 (40{sup 0}N, 32{sup 0}W) was used to compare how our new and existing calibrations performed for the Holocene and over the large scale change associated with Termination I.

  4. Stellar rotation periods determined from simultaneously measured Ca II H&K and Ca II IRT lines

    Science.gov (United States)

    Mittag, M.; Hempelmann, A.; Schmitt, J. H. M. M.; Fuhrmeister, B.; González-Pérez, J. N.; Schröder, K.-P.

    2017-11-01

    Aims: Previous studies have shown that, for late-type stars, activity indicators derived from the Ca II infrared-triplet (IRT) lines are correlated with the indicators derived from the Ca II H&K lines. Therefore, the Ca II IRT lines are in principle usable for activity studies, but they may be less sensitive when measuring the rotation period. Our goal is to determine whether the Ca II IRT lines are sufficiently sensitive to measure rotation periods and how any Ca II IRT derived rotation periods compare with periods derived from the "classical" Mount Wilson S-index. Methods: To analyse the Ca II IRT lines' sensitivity and to measure rotation periods, we define an activity index for each of the Ca II IRT lines similar to the Mount Wilson S-index and perform a period analysis for the lines separately and jointly. Results: For eleven late-type stars we can measure the rotation periods using the Ca II IRT indices similar to those found in the Mount Wilson S-index time series and find that a period derived from all four indices gives the most probable rotation period; we find good agreement for stars with already existing literature values. In a few cases the computed periodograms show a complicated structure with multiple peaks, meaning that formally different periods are derived in different indices. We show that in one case, this is due to data sampling effects and argue that denser cadence sampling is necessary to provide credible evidence for differential rotation. However, our TIGRE data for HD 101501 shows good evidence for the presence of differential rotation.

  5. The key role of topography in altering North Atlantic atmospheric circulation during the last glacial period

    Directory of Open Access Journals (Sweden)

    F. S. R. Pausata

    2011-10-01

    Full Text Available The Last Glacial Maximum (LGM; 21 000 yr before present was a period of low atmospheric greenhouse gas concentrations, when vast ice sheets covered large parts of North America and Europe. Paleoclimate reconstructions and modeling studies suggest that the atmospheric circulation was substantially altered compared to today, both in terms of its mean state and its variability. Here we present a suite of coupled model simulations designed to investigate both the separate and combined influences of the main LGM boundary condition changes (greenhouse gases, ice sheet topography and ice sheet albedo on the mean state and variability of the atmospheric circulation as represented by sea level pressure (SLP and 200-hPa zonal wind in the North Atlantic sector. We find that ice sheet topography accounts for most of the simulated changes during the LGM. Greenhouse gases and ice sheet albedo affect the SLP gradient in the North Atlantic, but the overall placement of high and low pressure centers is controlled by topography. Additional analysis shows that North Atlantic sea surface temperatures and sea ice edge position do not substantially influence the pattern of the climatological-mean SLP field, SLP variability or the position of the North Atlantic jet in the LGM.

  6. Fidelity of the Sr/Ca proxy in recording ocean temperature in the western Atlantic coral Siderastrea siderea

    Science.gov (United States)

    Kuffner, Ilsa B.; Roberts, Kelsey E.; Flannery, Jennifer A.; Morrison, Jennifer M.; Richey, Julie N.

    2017-01-01

    Massive corals provide a useful archive of environmental variability, but careful testing of geochemical proxies in corals is necessary to validate the relationship between each proxy and environmental parameter throughout the full range of conditions experienced by the recording organisms. Here we use samples from a coral-growth study to test the hypothesis that Sr/Ca in the coral Siderastrea siderea accurately records sea-surface temperature (SST) in the subtropics (Florida, USA) along 350 km of reef tract. We test calcification rate, measured via buoyant weight, and linear extension (LE) rate, estimated with Alizarin Red-S staining, as predictors of variance in the Sr/Ca records of 39 individual S. siderea corals grown at four outer-reef locations next to in-situ temperature loggers during two, year-long periods. We found that corals with calcification rates quality-control indicator during sample and drill-path selection when using long cores for SST paleoreconstruction. For our corals that passed this quality control step, the Sr/Ca-SST proxy performed well in estimating mean annual temperature across three sites spanning 350 km of the Florida reef tract. However, there was some evidence that extreme temperature stress in 2010 (cold snap) and 2011 (SST above coral-bleaching threshold) may have caused the corals not to record the temperature extremes. Known stress events could be avoided during modern calibrations of paleoproxies.Plain Language SummaryCoral skeletons are used to decipher past environmental conditions in the ocean because they live for centuries and produce annual growth bands much like tree rings. Along with measuring coral growth rates in the past, coral skeletons can be chemically sampled to get even more detailed information, like past seawater temperatures. In this study we tested the validity of the strontium-to-calcium (Sr/Ca) temperature proxy in the Massive Starlet Coral (Siderastrea siderea) by sampling 39 corals that were grown in the

  7. North Atlantic Surface and Deep-Water Hydrography during the Early Pliocene Warm Period

    Science.gov (United States)

    Voelker, A. H. L.; Evans, H. F.; Naafs, B. D.; Cavaleiro, C. D.; Rebotim, A.; Ventura, C.; Stein, R. H.; Channell, J. E. T.

    2014-12-01

    The early Pliocene, with atmospheric carbon dioxide concentrations at levels similar to today, is seen as a case study for Earth's future climate evolution. During this period the progressive closing of the Central American Seaway led to increased poleward heat and salt transport within the Atlantic with North Atlantic Deep Water (NADW) becoming warmer and saltier and resulting in an enhanced Atlantic Meridional Overturning Circulation (AMOC). In order to understand how stable the AMOC really was we produced millennial-scale (1-2 kyr) surface and deep-water records for IODP Site U1313 (41°N, 33°W, 3412m) for the interval from 3.4 to 4.1 Ma. This site is ideally located to monitor past AMOC changes with North Atlantic Drift waters at the surface and NADW in the deep. Although interglacial/glacial cycles are visible, the higher frequency oscillations recorded in both the planktonic G. ruber (white) and benthic Cibicidoides sp. δ18O records impede tuning to the LR04 stack (Lisiecki and Raymo, 2005). We therefore exploit a different approach: using the magnetic polarity chrons (Gilbert, Cochiti) as recorded at Site U1313 as framework, we tune our benthic δ18O record to that of ODP Site 1085 (on LR04 ages). The benthic δ13C record shows millennial-scale oscillations, and the values indicate nearly continuous NADW presence and confirm a strong AMOC, also during most of the glacial periods. Varying surface water conditions, especially during the younger interglacial periods, are reflected in the G. ruber isotope data and appear to be linked to salinity changes since they are not recorded in the alkenone sea-surface temperature data. Although glacial stages Gi 2 and Gi 4 show the expected higher benthic δ18O values, Gi 6 was the glacial period with the strongest impact on the AMOC as revealed by cooler, less ventilated surface waters and a less ventilated NADW. Overall, the AMOC was strong throughout, but experienced high frequency oscillations at a level similar to

  8. Multi-Centennial Record of North Atlantic Freshwater Variability since the Little Ice Age Archived in Coralline Algal Ba/Ca

    Science.gov (United States)

    Chan, P. T. W.; Halfar, J.; Adey, W.; Zack, T.

    2014-12-01

    Declining Arctic sea-ice cover in recent decades has driven large-scale freshwater transport into the North Atlantic, possibly influencing the strength of the Meridional Overturning Circulation and even global climate. However, due to the lack of long-term oceanographic observations, little is known about the natural freshwater variability of the Northwestern Atlantic. Crustose coralline algae Clathromorphum compactum are extremely long-lived shallow marine calcareous plants that are abundant along the subarctic eastern Canadian coastline. They are particularly well-suited as recorders of paleoclimate signals due to the formation of annual growth increments, allowing for the precise calendar dating and geochemical sampling of hard tissue. Here, we provide the first annually-resolved multi-centennial record of coralline algal Ba/Ca from Labrador, Canada, as a proxy for North Atlantic freshwater variability extending well into the Little Ice Age (LIA) (1665 AD). Barium-to-calcium ratios (Ba/Ca) from coralline algae have previously been used as an indicator of freshwater runoff. This is because barium-rich clay sediments are transported by terrestrial runoff into coastal waters, and barium is released from the clay minerals upon encountering more alkaline elements present in seawater. We observe higher algal barium concentrations during the LIA, followed by a steady decline to recent times. In addition, coralline algal Ba/Ca shows significant positive relationships to Hudson Strait runoff, as well as Canadian Arctic and North Atlantic sea-ice extent. This suggests that more riverine Ba is transported from the Hudson Strait into the Labrador Sea during periods of increased sea-ice cover. Multiyear sea-ice can block incoming solar radiation thereby diminishing the effects of nutrient scavenging by phytoplankton, resulting in a more conservative transport of Ba into northern Labrador. However as sea-ice continues to thin, more sunlight is able to penetrate through the

  9. High precision glacial-interglacial benthic foraminiferal Sr/Ca records from the eastern equatorial Atlantic Ocean and Caribbean Sea

    Science.gov (United States)

    Shen, Chuan-Chou; Hastings, David W.; Lee, Typhoon; Chiu, Chin-Hsin; Lee, Meng-Yang; Wei, Kuo-Yen; Edwards, R. Lawrence

    2001-08-01

    Glacial-interglacial variation in the marine Sr/Ca ratio has important implications for coral Sr thermometry [J.W. Beck et al., Science 257 (1992) 644-647]. A possible variation of 1-3% was proposed based on ocean models [H.M. Stoll and D.P. Schrag, Geochim. Cosmochim. Acta 62 (1998) 1107-1118]. Subsequently, studies have used fossil foraminifera to test this prediction [P.A. Martin et al., Geochem. Geophys. Geosyst. 1 (1999); H.M. Stoll et al., Geochim. Cosmochim. Acta 63 (1999) 3535-3547; H. Elderfield et al., Geochem. Geophys. Geosyst. 1 (2000)]. But whether some component of foraminiferal Sr/Ca variation can be uniquely ascribed to seawater Sr variation is still not clear. To address this question, we developed cleaning and analysis techniques and measured Sr/Ca ratios on individual shells of the modern benthic foraminifer Cibicidoides wuellerstorfi. We showed that different size shells have different Sr/Ca ratios; however, samples with shell sizes of 355-500 μm appear to have normally distributed Sr/Ca ratios (1σ=1.8%). For multi-shell measurements (with estimated errors of 0.12-0.39%), the ratio varied by as much as 7.2±0.5% during the last glaciation for two Caribbean records at the same site and by 3.7±0.5% over the past 40,000 yr for one record from the Sierra Leone Rise in the eastern equatorial Atlantic. The two Caribbean records are very similar indicating that the behavior of shell Sr uptake was identical locally and that the shell Sr/Ca ratio faithfully reflects the local environment. The Atlantic record differs from the Caribbean records by as much as several percent. Thus, the foraminiferal Sr/Ca changes cannot be solely due to changes in seawater Sr/Ca unless the glacial deep ocean had spatial variation in Sr/Ca well in excess of the modern ocean. Certain similarities between the three records do exist. Notably, the rate of change of Sr/Ca is similar between 9 and 0 ka (-0.25%/kyr) and between 25 and 16 ka (+0.16%/kyr). This suggests that

  10. Mosquitoes (Diptera: Culicidae) from crepuscular period in an Atlantic Forest area in Southern Brazil.

    Science.gov (United States)

    Orlandin, E; Santos, E B; Piovesan, M; Favretto, M A; Schneeberger, A H; Souza, V O; Muller, G A; Wagner, G

    2017-03-01

    Crepuscular period is one of the factors that may influence the biting activity of mosquitoes. Many of these insects have a peak activity in this period. The purpose of this study was to investigate the afternoon crepuscular activity of Culicidae in a remaining area of Atlantic Forest in western Santa Catarina, southern Brazil. Moreover, the possible influence of abiotic factors, the abundance and species richness were verified. In order to better analyze the influence of crepuscular period in specific composition and abundance of mosquitoes, the dusk was divided into three periods: pre-sunset, sunset and post-sunset. At the end of the study, nine hundred and eight four specimens distributed in 12 genera and 23 species were collected. Trichoprosopon pallidiventer (Lutz, 1905) (59.76%), Aedes crinifer (Theobald, 1903) (8.13%), Ae. scapularis (Rondani, 1848) (5.89%) were the most abundant species. Spring time presented the greatest abundance and species richness. During the study, among the three periods evaluated, pre-sunset had the greatest abundance and post-sunset the lowest. Pre-sunset and sunset had the greatest similarity between species. Regarding to the abiotic factors evaluated seven and 15 days before sampling, they did not present significant correlation for the three most abundant species. However, temperature had a positive correlation to these species. Moreover, the correlation between collected species and its possible role as vectors of etiological agents of diseases was discussed.

  11. Tracing Marine Cryptotephras in the North Atlantic during the Last Glacial Period

    Science.gov (United States)

    Abbott, Peter; Davies, Siwan; Griggs, Adam; Bourne, Anna

    2017-04-01

    patterns in the occurrence of these deposit types have been detected, the dominant controls at different sites explored and key regions of the North Atlantic with a greater likelihood for preserving isochronous deposits identified. Overall, these investigations have allowed a framework of isochronous marine cryptotephras to be defined for the last glacial period. The most widespread deposit is the rhyolitic phase of North Atlantic Ash Zone II, identified in 9 of the marine sequences and providing a direct tie-line to the Greenland ice-cores records. The framework is dominated by horizons with a basaltic composition, predominantly sourced from the Icelandic Grímsvötn volcanic system but horizons with Katla, Hekla, Kverkfjöll, Veidivötn and Vestmannaeyjar like compositions have also been isolated. Correlations to horizons in the Greenland ice-core tephra framework are being explored, however, this is a challenging process due to the large number of horizons with similar geochemical signatures in the records and the difference in temporal resolution and stratigraphic control between the ice and marine sequences.

  12. Precipitation over eastern South America and the South Atlantic Sea surface temperature during neutral ENSO periods

    Science.gov (United States)

    Bombardi, Rodrigo J.; Carvalho, Leila M. V.; Jones, Charles; Reboita, Michelle S.

    2014-03-01

    The dominant mode of coupled variability over the South Atlantic Ocean is known as "South Atlantic Dipole" (SAD) and is characterized by a dipole in sea surface temperature (SST) anomalies with centers over the tropical and the extratropical South Atlantic. Previous studies have shown that variations in SST related to SAD modulate large-scale patterns of precipitation over the Atlantic Ocean. Here we show that variations in the South Atlantic SST are associated with changes in daily precipitation over eastern South America. Rain gauge precipitation, satellite derived sea surface temperature and reanalysis data are used to investigate the variability of the subtropical and tropical South Atlantic and impacts on precipitation. SAD phases are assessed by performing Singular value decomposition analysis of sea level pressure and SST anomalies. We show that during neutral El Niño Southern Oscillation events, SAD plays an important role in modulating cyclogenesis and the characteristics of the South Atlantic Convergence Zone. Positive SST anomalies over the extratropical South Atlantic (SAD negative phase) are related to increased cyclogenesis near southeast Brazil as well as the migration of extratropical cyclones further north. As a consequence, these systems organize convection and increase precipitation over eastern South America.

  13. Development of the Wintertime Sr/Ca-SST Record from Red Sea Corals as a Proxy for the North Atlantic Oscillation

    Science.gov (United States)

    Bernstein, W. N.; Hughen, K. A.

    2009-12-01

    The North Atlantic Oscillation (NAO) is one of the most pronounced and influential patterns in winter atmospheric circulation variability. This meridional redistribution of atmospheric mass across the Atlantic Ocean produces large changes in the intensity, number and direction of storms generated within the basin, and the regional climate of surrounding continents. The NAO exerts a significant impact on society, through influences on agriculture, fisheries, water management, energy generation and coastal development. NAO effects on climate extend from eastern North America across Europe to the eastern Mediterranean and Middle East. Changes in NAO behavior during the late 20th century have been linked to global warming; yet despite its importance, the causes and long-term patterns of NAO variability in the past remain poorly understood. In order to better predict the influence of the NAO on climate in the future, it is critical to examine multi-century NAO variability. The Red Sea is an excellent location from which to generate long NAO records for two reasons. First, patterns of wintertime sea surface temperature (SST) and salinity (SSS) in the Red Sea are highly correlated with NAO variability (Visbeck et al. 2001; Hurrell et al. 2003). Second, the tropical/subtropical Red Sea region contains fast growing long-lived massive Porites spp. corals with annually banded skeletons. These corals are ideal for generating well-dated high-resolution paleoclimatic records that extend well beyond the instrumental period. Here we present a study of winter SST and NAO variability in the Red sea region based on coral Sr/Ca data. In 2008, we collected multiple drill cores ranging in length from 1 to 4.1 meters from Porites corals at six sites spanning a large SST gradient. Sr/Ca measurements from multiple corals will be regressed against 23 years of satellite SST data, expanding the SST range over which we calibrate. A sampling resolution of 0.5mm will yield greater than bi

  14. South Atlantic Sea Surface Temperature and its Relationship with Precipitation in Brazil During Neutral ENSO Periods

    Science.gov (United States)

    Bombardi, R. J.; Carvalho, L. V.; Jones, C.

    2012-12-01

    The dominant mode of coupled variability over the South Atlantic Ocean is known as "South Atlantic Dipole" (SAD) and is characterized by a dipole in sea surface temperature (SST) anomalies with centers over the tropical and the subtropical South Atlantic. Previous studies have shown that variations in SST related to SAD modulate large-scale patterns of precipitation over the Atlantic Ocean. Here we show that variations in the South Atlantic SST strongly impact daily precipitation over central-eastern Brazil (Fig. 1). Moreover, we examine the mechanisms whereby the South Atlantic SST anomalies influence the climate of the region. Rain gauge precipitation, satellite derived sea surface temperature and reanalysis data are used to investigate the variability of the subtropical and tropical South Atlantic and impacts on precipitation. SAD phases are assessed by performing Singular Value Decomposition (SVD) analysis of sea level pressure and SST anomalies. We show that during neutral ENSO events, SAD is an important role on the interaction tropics-extratropics. Positive SST anomalies over the subtropical South Atlantic (SAD negative phase) favor cyclogenesis as well as the migration of extratropical cyclones further north, increasing precipitation over central-eastern Brazil. We expect that the results from this study will contribute to climate monitoring and forecast.; Figure 1 - Composites of SST anomalies (shade) and precipitation (contour) during a) negative SAD events; b) positive SAD events. Difference between composites of SAD events (positive minus negative) for c) precipitation and d) SST. Shading in (c) and (d) indicate regions where the difference is statistically significant at 5% level according to the z-test of the difference of means. Contour interval equal 0.25 mm.day-1 in (a) and (b) and equal 0.5 mm.day-1 in (c).

  15. On the role of periodic structures in the lower jaw of the atlantic bottlenose dolphin (Tursiops truncatus)

    Energy Technology Data Exchange (ETDEWEB)

    Dible, S A; Flint, J A; Lepper, P A [Electronic and Electrical Engineering, Loughborough University, Loughborough, LE11 3TU (United Kingdom)], E-mail: james.flint@ieee.org

    2009-03-01

    This paper proposes the application of band-gap theory to hearing in the atlantic bottlenose dolphin (Tursiops truncatus). Using the transmission line modelling (TLM) technique and published computed tomography (CT) data of an atlantic bottlenose dolphin (Tursiops truncatus), a series of sound propagation experiments have been carried out. It is shown that the teeth in the lower jaw can be viewed as a periodic array of scattering elements which result in the formation of an acoustic stop band (or band gap) that is angular dependent. It is shown through simple and complex geometry simulations that performance enhancements such as improved gain and isolation between the two receive paths can be achieved. This mechanism has the potential to be exploited in direction-finding sonar.

  16. Data for evaluating the Sr/Ca temperature proxy with in-situ temperature in the western Atlantic coral Siderastrea siderea

    Science.gov (United States)

    Kuffner, Ilsa B.; Roberts, Kelsey E.; Flannery, Jennifer A.; Morrison, Jennifer M.; Richey, Julie

    2016-01-01

    Massive corals are used as environmental recorders throughout the tropics and subtropics to study environmental variability during time periods preceding ocean-observing instrumentation. However, careful testing of paleoproxies is necessary to validate the environmental-proxy record throughout a range of conditions experienced by the recording organisms. As part of the USGS Coral Reef Ecosystems Studies project (http://coastal.er.usgs.gov/crest/), we tested the hypothesis that the coral Siderastrea siderea faithfully records sea-surface temperature (SST) in the Sr/Ca record throughout the subtropical (Florida, USA) seasonal cycle along 350 km of reef tract. Coral samples were analyzed from thirty-nine corals growing in 3 to 4 m depth at Fowey Rocks (Biscayne National Park), Molasses Reef (Florida Keys National Marine Sanctuary, FKNMS), Sombrero Reef (FKNMS), and Pulaski Shoal (Dry Tortugas National Park). Temperatures were recorded with Onset® HOBO® Water Temp Pro V2 (U22-001) data loggers in duplicate at each site. Sr/Ca, Mg/Ca, calcification rate, and select underwater temperature data are provided here. The results of this experiment are interpreted in Kuffner et al. (in review). A larger temperature dataset, including the data provided here, is found in another data release Kuffner (2015), and a larger calcification-rate dataset is interpreted in Kuffner et al. (2013).Kuffner, I.B., K.E. Roberts, J.A. Flannery, J.M. Morrison, and J.N. Richey. In review. Fidelity of the Sr/Ca proxy in recording ocean temperature in the western Atlantic coral Siderastrea siderea.Kuffner, I.B., T.D. Hickey, and J.M. Morrison. 2013. Calcification rates of the massive coral Siderastrea siderea and crustose coralline algae along the Florida Keys (USA) outer-reef tract. Coral Reefs 32:987-997. http://link.springer.com/article/10.1007/s00338-013-1047-8Kuffner, I. B. (2015), Underwater temperature on off-shore coral reefs of the Florida Keys, U.S.A.: U.S. Geological Survey data

  17. Tropical Atlantic SSTS at the Last Glacial Maximum derived from Sr/Ca ratios of fossil coral

    Science.gov (United States)

    Cohen, A. L.; Saenger, C. P.

    2006-12-01

    The sensitivity of the tropics to climate change is a particularly controversial issue in paleoclimatology. At the heart of this controversy are disagreements amongst different proxy datasets regarding the amplitude of glacial-interglacial changes in temperature, particularly at the sea surface. Data obtained from the aragonitic skeletons of massive reef corals have contributed in no small measure to the debate, yielding LGM and deglacial SSTs 5-6°C cooler than today (Guilderson et al., 1994; McCulloch et al., 1999; Correge et al., 2004), that imply a high sensitivity of Earth's climate to changes in boundary conditions (Crowley, 2000). We used SIMS ion microprobe to analyze Sr/Ca ratios of small pieces of Montastrea coral retrieved from a Barbados drillcore (Guilderson et al., 2001). U/Th dates place the samples between 22 and 24 kyr BP. Localized areas of dissolution and re-growth of secondary (diagenetic) aragonite crystals were identified at centers of septa. Sr/Ca ratios of these crystals were higher than Sr/Ca ratios of original coral crystals preserved in adjacent fasciculi and yielded relatively cooler derived SSTs. The original coral crystals, recognized by their size and orientation, were selectively targeted for analysis using a 20 micron-diameter sample spot. Our calibration study using modern corals from Bermuda, St Croix (USVI) and Barbados indicates that Montastrea Sr/Ca is strongly correlated with SST and with annual extension (growth) rate (Saenger et al., 2006). Growth rate of the fossil corals was determined from measurement of daily growth bands identified in petrographic thin-sections. Application of a growth-dependent Sr/Ca-T calibration yielded Barbados SSTs that were, on average, 2.5°C cooler than today during the LGM and ~1°C cooler than today during Heinrich Event 2. Our LGM SSTs are consistent with the original CLIMAP estimates (CLIMAP, 1976) and with more recent Mg/Ca-based SSTs derived from calcitic foraminifera in the Caribbean

  18. Calibration and application of B/Ca, Cd/Ca, and δ11B in Neogloboquadrina pachyderma (sinistral) to constrain CO2 uptake in the subpolar North Atlantic during the last deglaciation

    Science.gov (United States)

    Yu, Jimin; Thornalley, David J. R.; Rae, James W. B.; McCave, Nick I.

    2013-06-01

    The North Atlantic and Norwegian Sea are prominent sinks of atmospheric CO2 today, but their roles in the past remain poorly constrained. In this study, we attempt to use B/Ca and δ11B ratios in the planktonic foraminifera Neogloboquadrina pachyderma (sinistral variety) to reconstruct subsurface water pH and pCO2 changes in the polar North Atlantic during the last deglaciation. Comparison of core-top results with nearby hydrographic data shows that B/Ca in N. pachyderma (s) is mainly controlled by seawater B(OH)4-/HCO3- with a roughly constant partition coefficient KD=B>/CaCaCO3BOH 4->/HCO3>¯seawater of 1.48 ± 0.15 × 10-3 (2σ), and δ11B in this species is offset below δ11B of the borate in seawater by 3.38 ± 0.71‰ (2σ). These values represent our best estimates with the sparse available hydrographic data close to our core-tops. More culturing and sediment trap work is needed to improve our understanding of boron incorporation into N. pachyderma (s). Application of a constant KD of 1.48 × 10-3 to high resolution N. pachyderma (s) B/Ca records from two adjacent cores off Iceland shows that subsurface pCO2 at the habitat depth of N. pachyderma (s) ( 50 m) generally followed the atmospheric CO2 trend but with negative offsets of 10-50 ppmv during 19-10 ka. These B/Ca-based reconstructions are supported by independent estimates from low-resolution δ11B measurements in the same cores. We also calibrate and apply Cd/Ca in N. pachyderma (s) to reconstruct nutrient levels for the same down cores. Like today's North Atlantic, past subsurface pCO2 variability off Iceland was significantly correlated with nutrient changes that might be linked to surface nutrient utilization and mixing within the upper water column. Because surface pCO2 (at 0 m water depth) is always lower than at deeper depths and if the application of a constant KD is valid, our results suggest that the polar North Atlantic has remained a CO2 sink during the calcification seasons of N. pachyderma

  19. Substantial Downregulation of Myogenic Transcripts in Skeletal Muscle of Atlantic Cod during the Spawning Period

    Science.gov (United States)

    Edvardsen, Vigdis

    2016-01-01

    Gonadal maturation is an extremely energy consuming process for batch spawners and it is associated with a significant decrease in growth and seasonal deterioration in flesh quality. Our knowledge about the molecular mechanisms linking sexual maturation and muscle growth is still limited. In the present study, we performed RNA-Seq using 454 GS-FLX pyrosequencing in fast skeletal muscle sampled from two-year-old Atlantic cod (Gadus morhua) at representative time points throughout the reproductive cycle (August, March and May). In total, 126,937 good quality reads were obtained, with 546 nucleotide length and 52% GC content on average. RNA-Seq analysis using the CLC Genomics Workbench with the Atlantic cod reference UniGene cDNA data revealed 59,581 (46.9%) uniquely annotated reads. Pairwise comparison for expression levels identified 153 differentially expressed UniGenes between time points. Notably, we found a significant suppression of myh13 and myofibrillar gene isoforms in fast skeletal muscle during the spawning season. This study uncovered a large number of differentially expressed genes that may be influenced by gonadal maturation, thus representing a significant contribution to our limited understanding of the molecular mechanisms regulating muscle wasting and regeneration in batch spawners during their reproductive cycle. PMID:26844771

  20. Fidelity of the Sr/Ca proxy in recording ocean temperature in the western Atlantic coral Siderastrea siderea

    Science.gov (United States)

    Kuffner, Ilsa B.; Roberts, Kelsey E.; Flannery, Jennifer A.; Morrison, Jennifer M.; Richey, Julie

    2017-01-01

    Massive corals provide a useful archive of environmental variability, but careful testing of geochemical proxies in corals is necessary to validate the relationship between each proxy and environmental parameter throughout the full range of conditions experienced by the recording organisms. Here we use samples from a coral-growth study to test the hypothesis that Sr/Ca in the coral Siderastrea siderea accurately records sea-surface temperature (SST) in the subtropics (Florida, USA) along 350 km of reef tract. We test calcification rate, measured via buoyant weight, and linear extension (LE) rate, estimated with Alizarin Red-S staining, as predictors of variance in the Sr/Ca records of 39 individual S. siderea corals grown at four outer-reef locations next to in-situ temperature loggers during two, year-long periods. We found that corals with calcification rates mean annual temperature across three sites spanning 350 km of the Florida reef tract. However, there was some evidence that extreme temperature stress in 2010 (cold snap) and 2011 (SST above coral-bleaching threshold) may have caused the corals not to record the temperature extremes. Known stress events could be avoided during modern calibrations of paleoproxies.

  1. Contaminant levels in Norwegian farmed Atlantic salmon (Salmo salar) in the 13-year period from 1999 to 2011.

    Science.gov (United States)

    Nøstbakken, Ole Jakob; Hove, Helge T; Duinker, Arne; Lundebye, Anne-Katrine; Berntssen, Marc H G; Hannisdal, Rita; Lunestad, Bjørn Tore; Maage, Amund; Madsen, Lise; Torstensen, Bente E; Julshamn, Kåre

    2015-01-01

    Environmental pollutants such as dioxins and PCBs, heavy metals, and organochlorine pesticides are a global threat to food safety. In particular, the aquatic biota can bioaccumulate many of these contaminants potentially making seafood of concern for chronic exposure to humans. The main objective was to evaluate trends of contaminant levels in Norwegian farmed Atlantic salmon in light of the derived tolerable intakes. Through an EU-instigated surveillance programme, the Norwegian Food Safety Authority (NFSA) has between 1999 and 2011 collected more than 2300 samples of Norwegian farmed Atlantic salmon (Salmo salar) for contaminant analyses. The fillets of these fish were homogenised and analysed for dioxins, PCBs, heavy metals and organochlorine pesticides. The levels of the contaminants mercury, arsenic, dioxins, dioxin-like PCBs and DDT in Norwegian farmed salmon fillet have decreased during our period of analyses. The levels of cadmium, lead and several organochlorine pesticides were too close to the limit of quantification to calculate time trends. For PCB6 and quantifiable amounts of pesticides, except DDT, stable levels were observed. The contaminant levels in Norwegian farmed salmon have generally decreased between 1999 and 2011. Excluding other dietary sources, the levels of dioxins and dioxin-like PCBs in 2011 allowed consumption of up to 1.3kg salmon per week to reach the tolerable weekly intake. The group of contaminants which was the limiting factor for safe consumption of Norwegian farmed salmon, based on currently established TWI values, is the sum of dioxins and dioxin-like PCBs. Copyright © 2014. Published by Elsevier Ltd.

  2. Reproduction period of Mimagoniates microlepis, from an Atlantic Forest Stream in Southern Brazil

    Directory of Open Access Journals (Sweden)

    Marcelo Rennó Braga

    2008-04-01

    Full Text Available Mimagoniates microlepis was collected between January and December/2002. Three sample points were chosen at higher, medium and lower portions of Ribeirão river, located at the east of Paraná state. The reproduction period was observed by the frequency of gonad developmental stages, variation of the gonosomatic relation (RGS and gonad condition (K. The average length at the first sexual maturity (L50 and the average length when 100% of individuals were adults (L100 were calculated. The intensity of the reproductive activity (IAR was estimated at each sample point. The reproduction period started in the winter and ended at the end of spring. The high values of IAR encountered demonstrated that the reproductive activity occurred in the whole study area, mainly at the middle portion of the river. Apparently M. microlepis synchronize its fecundation and spawning with the rain regimes using the most suitable times for the cospecific encounters and offspring survival.Exemplares de Mimagoniates microlepis foram coletados entre janeiro e dezembro de 2002. Foram escolhidos três pontos amostrais localizados em regiões a montante, média e a jusante do rio Ribeirão no litoral do Paraná. A época reprodutiva foi determinada através da freqüência de estágios de desenvolvimento das gônadas, índice gonadosomático (RGS e fator de condição gonadal (K. O comprimento médio da primeira maturação (L50 e o comprimento médio em que 100% dos indivíduos são adultos (L100 foi calculado. Também foi estimado o índice de atividade reprodutiva (IAR em cada ponto amostral. O período reprodutivo teve inicio durante o inverno e terminou ao final da primavera. Os valores altos do IAR demonstram que a atividade reprodutiva ocorre em toda área estudada e principalmente na porção média do rio. Aparentemente M. microlepis sincroniza sua fecundação e desova com o ciclo das chuvas, utilizando os momentos mais adequados para encontros coespecíficos e para

  3. 77 FR 75654 - Nomination Period Extension for the Carrizo Plain National Monument Advisory Council, CA

    Science.gov (United States)

    2012-12-21

    ... Bureau of Land Management Nomination Period Extension for the Carrizo Plain National Monument Advisory... positions on the Carrizo Plain National Monument Advisory Council (MAC) to December 31, 2012. MAC members... National Monument. ADDRESSES: Nominations should be sent to Johna Hurl, Monument Manager, Bureau of Land...

  4. FIT FOR PRINT: DEVELOPING AN INSTITUTIONAL MODEL OF SCIENTIFIC PERIODICAL PUBLISHING IN ENGLAND, 1665-CA. 1714.

    Science.gov (United States)

    Moxham, N

    2015-09-20

    This paper explores the contested afterlife of Philosophical Transactions following the death of its founder, Henry Oldenburg. It investigates the complex interrelation between the institution and the periodical at a time when the latter was supposedly independent, and outlines the competing proposals for institutional publishing in science contemplated in the Royal Society, linking some publications that were actually attempted to those proposals and to the Society's attempts to revitalize its experimental programme between 1677 and 1687. It argues that the Society was concerned to produce experimental natural knowledge over which it could claim ownership, and intended this work for publication in other venues than Transactions, whereas the periodical was seen as a more suitable site for work reported to the Society than for research that the institution had primarily produced. It was only from the early 1690s, after the collapse of the Society's experimental programme, that Transactions gradually became a more straightforward reflection of the mainstream of Royal Society activity, paving the way for its formal reinvention as the official publication of the Society in 1752.

  5. Environmental Controls on Mg/Ca in Neogloboquadrina incompta: A Core-Top Study From the Subpolar North Atlantic

    Science.gov (United States)

    Morley, Audrey; Babila, Tali L.; Wright, James; Ninnemann, Ulysses; Kleiven, Kikki; Irvali, Nil; Rosenthal, Yair

    2017-12-01

    Magnesium/calcium paleothermometry is an established tool for reconstructing past surface and deep-sea temperatures. However, our understanding of nonthermal environmental controls on the uptake of Mg into the calcitic lattice of foraminiferal tests remains limited. Here we present a combined analysis of multiple trace element/calcium ratios and stable isotope (δ18O and δ13C) geochemistry on the subpolar planktonic foraminifera Neogloboquadrina incompta to assess the validity of Mg/Ca as a proxy for surface ocean temperature. We identify small size-specific offsets in Mg/Ca and δ18Oc values for N. incompta that are consistent with depth habitat migration patterns throughout the life cycle of this species. Additionally, an assessment of nonthermal controls on Mg/Ca values reveals that (1) the presence of volcanic ash, (2) the addition of high-Mg abiotic overgrowths, and (3) ambient seawater carbonate chemistry can have a significant impact on the Mg/Ca-to-temperature relationship. For carbonate-ion concentrations of values > 200 μmol kg-1, we find that temperature exerts the dominant control on Mg/Ca values, while at values < 200 μmol kg-1 the carbonate-ion concentration of seawater increases the uptake of Mg, thereby resulting in higher-than-expected Mg/Ca values at low temperatures. We propose two independent correction schemes to remove the effects of volcanic ash and carbonate-ion concentration on Mg/Ca values in N. incompta within the calibration data set. Applying the corrections improves the fidelity of past ocean temperature reconstructions.

  6. The wave climate of the Northeast Atlantic over the period 1955-1994: the WASA wave hindcast

    Energy Technology Data Exchange (ETDEWEB)

    Guenther, H.; Rosenthal, W.; Stawarz, M. [GKSS-Forschungszentrum Geesthacht GmbH (Germany). Inst. fuer Gewaesserphysik; Carretero, J.C.; Gomez, M.; Lozano, I.; Serrano, O. [Programa de Clima Maritimo (Puertos del Estado), Madrid (Spain); Reistad, M. [Det Norske Meteorologiske Inst., Bergen (Norway)

    1997-12-31

    The European project ``waves and storms in the North Atlantic`` (WASA) has been set up to prove, or to disprove, hypotheses of a worsening storm and wave climate in the Northeast Atlantic and adjacent seas in the present century. A major obstacle for assessing changes in storm and wave conditions are inhomogeneities in the observational records, both in the local observations and in the analysed products, which usually produce an artificial increase of extreme winds and waves. Therefore, changes in the wave climate were assessed with a state-of-the-art wave model using wind analyses. Within the scope of the WASA project, a 40 year reconstruction (1955-1994) of the wave climate in the North Atlantic was completed using the WAM wave model. The input wind fields were assumed to be reasonably homogeneous with time in the area south of 70 N and east of 20 W, and it was expected that the hindcast wave data would reliably describe the space-time evolution of wave conditions in this area. The results of the hindcast experiment are presented in this article. The main conclusion was that the wave climate in most of the Northeast Atlantic and in the North Sea has undergone significant variations on time scales of decades. Part of variability was found to be related to the North Atlantic oscillation. As a general result we noted an increase of the maximum annual significant wave height over the last 40 years of about 5 to 10 cm/year for large parts of the Northeast Atlantic, north of the North Sea. There was also a slight increase of probabilities of high waves derived from conventional extreme value statistics in northwest approaches to the North Sea. Similar trends of the extreme waves were found in a scenario of future wave climate at a time of doubled C0{sub 2} concentration in the atmosphere. (orig.) 28 refs.

  7. Centella asiatica (L. Leaf Extract Treatment During the Growth Spurt Period Enhances Hippocampal CA3 Neuronal Dendritic Arborization in Rats

    Directory of Open Access Journals (Sweden)

    K. G. Mohandas Rao

    2006-01-01

    Full Text Available Centella asiatica (CeA is a creeping plant growing in damp places in India and other Asian countries. The leaves of CeA are used for memory enhancement in the Ayurvedic system of medicine, an alternative system of medicine in India. In this study, we have investigated the effect during the rat growth spurt period of CeA fresh leaf extract treatment on the dendritic morphology of hippocampal CA3 neurons, one of the regions of the brain concerned with learning and memory. Neonatal rat pups (7 days old were fed with 2, 4 or 6 ml kg−1 body weight of fresh leaf extract of CeA for 2, 4 or 6 weeks. After the treatment period the rats were killed, their brains were removed and the hippocampal neurons were impregnated with silver nitrate (Golgi staining. Hippocampal CA3 neurons were traced using a camera lucida, and dendritic branching points (a measure of dendritic arborization and intersections (a measure of dendritic length were quantified. These data were compared with data for age-matched control rats. The results showed a significant increase in the dendritic length (intersections and dendritic branching points along the length of both apical and basal dendrites in rats treated with 4 and 6 ml kg−1 body weight per day of CeA for longer periods of time (i.e. 4 and 6 weeks. We conclude that the constituents/active principles present in CeA fresh leaf extract have a neuronal dendritic growth stimulating property; hence, the extract can be used for enhancing neuronal dendrites in stress and neurodegenerative and memory disorders.

  8. Reconstruct the past thermocline circulation in the Atlantic: calcification depths and Mg/Ca-temperature calibrations for 6 deep-dwelling planktonic foraminifera

    Science.gov (United States)

    Cleroux, C.; deMenocal, P.; Arbuszewski, J.; Linsley, B.

    2012-04-01

    The subtropical cells are shallow meridional overturning circulations driven by the atmospheric circulation and the deep thermohaline circulation. They connect the mid-latitude and the tropic, release latten heat to the atmosphere and impact climate on decadal to longer time scale. The upper water column temperature and salinity structures of the ocean reflect this circulation. We present proxies to study these past structures. We performed stable oxygen isotope (δ18O) and trace element ratio measurements on one surface-dwelling (G. ruber)1 and six deep-dwelling planktonic foraminifera species (N. dutertrei, G. inflata, G. tumida, G. truncatulinoides, G. hirsuta and G. crassaformis) on 66 coretops spanning from 35°N to 20°S along the Mid-Atlantic ridge. Comparison between measured δ18O and predicted δ18O (using water column temperature and seawater δ18O), shows that N. dutertrei, G. tumida, G. hirsuta and G. crassaformis keep the same apparent calcification depth along the transect (respectively: 125m, 150m, 700m and 800m). Calcification at two depth levels was also tested. For the six deep-dwelling species, we establish Mg/Ca-temperature calibrations with both atlas temperature at the calcification depth and isotopic temperature. We present Mg/Ca-temperature equations for species previously very poorly calibrated. The δ18O and temperature (Mg/Ca derived) on the six planktonic foraminifera species faithfully reproduce the modern water column structure of the upper 800 m depth, establishing promising proxies for past subsurface reconstruction. 1 Arbuszewski, J. J., P. B. deMenocal, A. Kaplan, and C. E. Farmer (2010), On the fidelity of shell-derived δ18Oseawater estimates, Earth and Planetary Science Letters, 300(3-4), 185-196.

  9. Inter-annual variability of aerosol optical depth over the tropical Atlantic Ocean based on MODIS-Aqua observations over the period 2002-2012

    Science.gov (United States)

    Gkikas, Antonis; Hatzianastassiou, Nikolaos

    2013-04-01

    The tropical Atlantic Ocean is affected by dust and biomass burning aerosol loads transported from the western parts of the Saharan desert and the sub-Sahel regions, respectively. The spatial and temporal patterns of this transport are determined by the aerosol emission rates, their deposition (wet and dry), by the latitudinal shift of the Intertropical Convergence Zone (ITCZ) and the prevailing wind fields. More specifically, in summer, Saharan dust aerosols are transported towards the Atlantic Ocean, even reaching the Gulf of Mexico, while in winter the Atlantic Ocean transport takes place in more southern latitudes, near the equator, sometimes reaching the northern parts of South America. In the later case, dust is mixed with biomass burning aerosols originating from agricultural activities in the sub-Sahel, associated with prevailing north-easterly airflow (Harmattan winds). Satellite observations are the appropriate tool for describing this African aerosol export, which is important to atmospheric, oceanic and climate processes, offering the advantage of complete spatial coverage. In the present study, we use satellite measurements of aerosol optical depth at 550nm (AOD550nm), on a daily and monthly basis, derived from MODIS-Aqua platform, at 1ox1o spatial resolution (Level 3), for the period 2002-2012. The primary objective is to determine the pixel-level and regional mean anomalies of AOD550nm over the entire study period. The regime of the anomalies of African export is interpreted in relation to the aerosol source areas, precipitation, wind patterns and temporal variability of the North Atlantic Oscillation Index (NAOI). In order to ensure availability of AOD over the Sahara desert, MODIS-Aqua Deep Blue products are also used. As for precipitation, Global Precipitation Climatology Project (GPCP) data at 2.5ox2.5o are used. The wind fields are taken from the National Center for Environmental Prediction (NCEP). Apart from the regime of African aerosol export

  10. Comparison of the response of Atlantic cod ( Gadus morhua) in the high-latitude regions of the North Atlantic during the warm periods of the 1920s-1960s and the 1990s-2000s

    Science.gov (United States)

    Drinkwater, Ken

    2009-10-01

    Concern about future anthropogenic warming has lead to demands for information on what might happen to fish and fisheries under various climate-change scenarios. One suggestion has been to use past events as a proxy for what will happen in the future. In this paper a comparison between the responses of Atlantic cod ( Gadus morhua) to two major warm periods in the North Atlantic during the 20th century is carried out to determine how reliable the past might be as a predictor of the future. The first warm period began during the 1920s, remained relatively warm through the 1960s, and was limited primarily to the northern regions (>60°N). The second warm period, which again covered the northern regions but also extended farther south (30°N), began in the 1990s and has continued into the present century. During the earlier warm period, the most northern of the cod stocks (West Greenland, Icelandic, and Northeast Arctic cod in the Barents Sea) increased in abundance, individual growth was high, recruitment was strong, and their distribution spread northward. Available plankton data suggest that these cod responses were driven by bottom-up processes. Fishing pressure increased during this period of high cod abundance and the northern cod stocks began to decline, as early as the 1950s in the Barents Sea but during the 1960s elsewhere. Individual growth declined as temperatures cooled and the cod distributions retracted southward. During the warming in the 1990s, the spawning stock biomass of cod in the Barents Sea again increased, recruitment rose, and the stock spread northward, but the individual growth did not improve significantly. Cod off West Greenland also have shown signs of improving recruitment and increasing biomass, albeit they are still very low in comparison to the earlier warming period. The abundance of Icelandic cod, on the other hand, has remained low through the recent warm period and spawning stock biomass and total biomass are at levels near the

  11. Reduced admixture of North Atlantic Deep Water to the deep central South Pacific during the last two glacial periods

    Science.gov (United States)

    Molina-Kescher, Mario; Frank, Martin; Tapia, Raúl; Ronge, Thomas A.; Nürnberg, Dirk; Tiedemann, Ralf

    2016-06-01

    The South Pacific is a sensitive location for the variability of the global oceanic thermohaline circulation given that deep waters from the Atlantic Ocean, the Southern Ocean, and the Pacific Basin are exchanged. Here we reconstruct the deep water circulation of the central South Pacific for the last two glacial cycles (from 240,000 years ago to the Holocene) based on radiogenic neodymium (Nd) and lead (Pb) isotope records complemented by benthic stable carbon data obtained from two sediment cores located on the flanks of the East Pacific Rise. The records show small but consistent glacial/interglacial changes in all three isotopic systems with interglacial average values of -5.8 and 18.757 for ɛNd and 206Pb/204Pb, respectively, whereas glacial averages are -5.3 and 18.744. Comparison of this variability of Circumpolar Deep Water (CDW) to previously published records along the pathway of the global thermohaline circulation is consistent with reduced admixture of North Atlantic Deep Water to CDW during cold stages. The absolute values and amplitudes of the benthic δ13C variations are essentially indistinguishable from other records of the Southern Hemisphere and confirm that the low central South Pacific sedimentation rates did not result in a significant reduction of the amplitude of any of the measured proxies. In addition, the combined detrital Nd and strontium (87Sr/86Sr) isotope signatures imply that Australian and New Zealand dust has remained the principal contributor of lithogenic material to the central South Pacific.

  12. Shipwreck rates and tree rings suggest reduced North Atlantic tropical cyclone activity during the Maunder Minimum.

    Science.gov (United States)

    Harley, G. L.; Trouet, V.; Dominguez Delmas, M.

    2014-12-01

    The observational record of North Atlantic TCs is too short to inform our understanding of decadal-scale climatic controls on TC regimes. We combined two new annual-resolution proxies of Atlantic storm activity to extend the observational TC record back to the 16th Century. A tree-growth suppression chronology (1707-2010 CE) from the Florida Keys, U.S.A. captures 91% of observed North Atlantic TCs (1850-2010 CE) and shares significant peak events with a documentary time series of Spanish shipwrecks in the Caribbean (1495-1820). Decadal-scale shipwreck rates were lowest during the Maunder Minimum (ca. 1645-1715), indicating that cooler Atlantic sea surface temperatures (SSTs) during this period reduced Caribbean TC activity. Our results support global-scale climate proxy data and suggest that cooler tropical Atlantic SSTs and a generally negative mode of the North Atlantic Oscillation during the Little Ice Age reduced TC frequency.

  13. Beneficial effects of bumetanide in a CaV1.1-R528H mouse model of hypokalaemic periodic paralysis.

    Science.gov (United States)

    Wu, Fenfen; Mi, Wentao; Cannon, Stephen C

    2013-12-01

    Transient attacks of weakness in hypokalaemic periodic paralysis are caused by reduced fibre excitability from paradoxical depolarization of the resting potential in low potassium. Mutations of calcium channel and sodium channel genes have been identified as the underlying molecular defects that cause instability of the resting potential. Despite these scientific advances, therapeutic options remain limited. In a mouse model of hypokalaemic periodic paralysis from a sodium channel mutation (NaV1.4-R669H), we recently showed that inhibition of chloride influx with bumetanide reduced the susceptibility to attacks of weakness, in vitro. The R528H mutation in the calcium channel gene (CACNA1S encoding CaV1.1) is the most common cause of hypokalaemic periodic paralysis. We developed a CaV1.1-R528H knock-in mouse model of hypokalaemic periodic paralysis and show herein that bumetanide protects against both muscle weakness from low K+ challenge in vitro and loss of muscle excitability in vivo from a glucose plus insulin infusion. This work demonstrates the critical role of the chloride gradient in modulating the susceptibility to ictal weakness and establishes bumetanide as a potential therapy for hypokalaemic periodic paralysis arising from either NaV1.4 or CaV1.1 mutations.

  14. Aerosol light absorption in the North Atlantic: trends and seasonal characteristics during the period 1989 to 2003

    Directory of Open Access Journals (Sweden)

    C. Junker

    2006-01-01

    Full Text Available Aerosol light attenuation on quartz fibre filters has been measured since February 1989 at the Mace Head Atmospheric Research station near Carna, Co. Galway, Ireland, using an Aethalometer. The frequency of occurrence of the hourly averaged aerosol absorption data is found to be bimodally distributed. The two modes result from clean marine air and anthropogenically polluted continental air both being advected to the station dependent on the prevailing wind direction. The hourly averages of the marine portion of the aerosol light absorption are found to follow closely a lognormal distribution with a geometric mean of 0.310 Mm-1. The hourly averages of continental sector aerosol absorption are neither normally nor lognormally distributed and have an arithmetic mean of 6.36 Mm-1, indicating the presence of anthropogenic sources for BC east of the Mace Head station. The time series of the monthly averaged attenuation coefficient σatt of both marine and continental sector aerosol shows an increase from 1989 to 1997 and a levelling off thereafter. The monthly maximum of marine sector σatt is found in May. Trend and seasonal characteristics of the clean marine aerosol attenuation coefficients observed at Mace Head appear to be driven by meteorological factors, as indicated by rainfall data and by trends in the North Atlantic Oscillation (NAO indices. The observed increasing trends of the continental sector σatt from 1989 up to 1997 are possibly related to changes in BC emissions over Ireland, calculated from UNSTAT (2002 fuel consumption data.

  15. Swell and Wind-Sea Distributions over the Mid-Latitude and Tropical North Atlantic for the Period 2002–2008

    Directory of Open Access Journals (Sweden)

    Eduardo G. G. de Farias

    2012-01-01

    Full Text Available We present an analysis of wind-sea and swell fields for mid-latitude and tropical Atlantic for the period 2002–2008 using a combination of satellite data (altimeter significant wave height and scatterometer surface winds and model results (spectrum peak wave period and propagation direction. Results show a dominance of swell over wind-sea regimes throughout the year. A small but clear decrease in swell energy and an associated increase in wind-sea potential growth were observed in the NE trade winds zone. A seasonal summertime increase in wind-sea energy in the Amazon River mouth and adjacent shelf region and in African coast was apparent in the results, probably associated to a strengthening of the alongshore trade winds in these regions. Albeit with a significantly smaller energy contribution of wind-seas as compared to swell energy, we could say that a kind of mixed seas is more evident in the trade winds region, with the remaining area being highly dominated by swell energy. An analysis of wave-age shows the absence of young-seas. Only ~2% of all data points was classified as wind-sea, a classification confirmed by a fit to a theoretical relation between wind speed, peak period, and significant wave height for fully developed wind-seas.

  16. In search of "Organ III" strata-a sedimentary record of the Medieval Warm Period (ca. AD 900 to 1300)

    Science.gov (United States)

    The period AD 900 to 1300, internationally referred to as the Medieval Warm Period, is a critical time for the archaeological record of the Southwestern USA. During the Medieval Warm Period both alluvial and eolian sedimentation increased, but not to the magnitude of the middle Holocene (the Altithe...

  17. A seesaw in Mediterranean precipitation during the Roman Period linked to millennial-scale changes in the North Atlantic

    NARCIS (Netherlands)

    Dermody, B.; Boer, H.J. de; Bierkens, M.F.P.; Weber, S.L.; Wassen, M.J.; Dekker, S.C.

    2012-01-01

    We present a reconstruction of the change in climatic humidity around the Mediterranean between 3000– 1000 yr BP. Using a range of proxy archives and model simulations we demonstrate that climate during this period was typified by a millennial-scale seesaw in climatic humidity between Spain and

  18. Impact of volcanism on the evolution of Lake Van (eastern Anatolia) III: Periodic (Nemrut) vs. episodic (Süphan) explosive eruptions and climate forcing reflected in a tephra gap between ca. 14 ka and ca. 30 ka

    Science.gov (United States)

    Schmincke, Hans-Ulrich; Sumita, Mari

    2014-09-01

    Fifteen Lateglacial to Holocene rhyolitic, dominantly primary tephra layers piston-cored and drilled (ICDP Paleovan drilling project) in western Lake Van (eastern Anatolia, Turkey) were precisely correlated to either of the two adjacent and active large volcanoes Nemrut and Süphan based on shard textures, mineralogy and mineral and glass compositions. The young peralkaline (comenditic to pantelleritic) primary rhyolitic Nemrut tephras are characterized by anorthoclase, hedenbergitic to augitic clinopyroxene, fayalitic olivine, minor quartz, and rare accessory chevkinite and zircon. Phenocrysts in subalkaline primary rhyolitic Süphan tephras are chiefly oligoclase-labradorite, with minor K-rich sanidine in some, biotite, amphibole, hypersthene, rare augitic clinopyroxene, relatively common allanite and rare zircon. Two contrasting explosive eruptive modes are distinguished from each other: episodic (Süphan) and periodic (Nemrut). The Lateglacial Süphan tephra swarm covers a short time interval of ca. 338 years between ca. 13,078 vy BP and 12,740 vy BP, eruptions having occurred statistically every ca. 42 years with especially short intervals between V-11 (reworked) and V-14. Causes for the strongly episodic Süphan explosive behavior might include seismic triggering of a volcano-magma system unable to erupt explosively without the benefit of external triggering, as reflected in pervasive faulting preceding the Süphan tephra swarm. Seismic triggering may have caused the rise of more mafic ("trachyandesitic") parent magma, heating near-surface pockets of highly evolved magma - that might have formed silicic domes during this stage of volcano evolution - resulting in ascent and finally explosive fragmentation of magma essentially by external factors, probably significantly enhanced by magma-water/ice interaction. Explosive eruptions of the Nemrut volcano system, interpreted to be underlain by a large fractionating magma reservoir, follow a more periodic mode of (a

  19. Early enrichment effects on brain development in hatchery-reared Atlantic salmon (Salmo salar): no evidence for a critical period

    DEFF Research Database (Denmark)

    Näslund, Joacim; Aarestrup, Kim; Thomassen, Søren T.

    2012-01-01

    of structurally enriched trays. We show that increased structural complexity during early rearing increased brain size in all investigated brain substructures. However, these effects disappeared over time after transfer to barren tanks for external feeding. Parallel to the hatchery study, a group of salmon parr...... was released into nature and recaptured at smoltification. These stream-reared smolts developed smaller brains than the hatchery reared smolts, irrespective of initial enrichment treatment. These novel findings do not support the hypothesis that there is a critical early period determining the brain growth...... trajectory. In contrast, our results indicate that brain growth is plastic in relation to environment. In addition, we show allometric growth in brain substructures over juvenile development, which suggests that comparisons between groups of different body size should be made with caution. These results can...

  20. New results to discuss possibility of irrigation in Bat (Wadi Sharsah, northwestern Oman) before Hafit period (ca. 3100-2700 BCE)

    Science.gov (United States)

    Fouache, Eric; Desruelles, Stéphane; Eddargach, Wassel; Cammas, Cecilia; Wattez, Julia; Martin, Chloé; Tengberg, Margareta; Beuzen-Waller, Tara; Cable, Charlotte; Thornton, Christopher

    2014-05-01

    Registered as a World Heritage Site by UNESCO in 1989, the extensive archaeological site of Bat is situated within the Wadi Sharsah and around the modern village and palm grove of Bat, 24 km from the modern city of Ibri in northwestern Oman. The archaeological remains from the Bronze Age excavated by the Bat Archaeological Project are located in two mains areas. The northern area consists of a chain of low limestone hills cut by wadi tributaries leading to the main Wadi Sharsah. It is characterised by an exceptionnally high density of graves from two successive Bronze Age periods : Hafit (ca. 3100-2700 BCE) and Umm an-Nar (ca. 2700-2000 BCE). South of the Bat cemetery, in the flat part of the valley, there are several large circular structures (known historically as « towers ») and remains from both Hafit and Umm an-Nar periods, as well as later periods. Geomorphological mapping of the floodplain, associated with archaeological survey, have identified walls suggesting that during the Umm an-Nar period there was a system of irrigation which controlled flood water. Sedimentological, malacological, C14 dating and micromorphological studies of a 10 m long and 2.5 m high section located 143 m northeast of the Tower 1146 on the left bank of a small tributary of the Wadi Sharsah provide strong argument for the presence of an irrigation system that began before the Hafit period. New C14 datings confirm this hypothesis. Botanical macro-remains collected during the excavation of early Bronze Age structures at Bat further indicate the presence of date palm gardens since the 3rd millenium BCE allowing the cultivation of several crop species, in particular cereals. Most generally the global palaeoenvironmental reconstruction from our data supports a model of a general trend of aridification from Bronze Age to iron Age. Key words : Bronze Age, Holocene, Geomoephology, Micromorphology, Irrigation, Oman.

  1. The synchronization of palaeoclimatic events in the North Atlantic region during Greenland Stadial 3 (ca 27.5 to 23.3 kyr b2k)

    DEFF Research Database (Denmark)

    Hibbert, F.D.; Peters, C.; Rasmussen, Sune Olander

    2012-01-01

    Two high resolution marine sediment cores located 83 km apart in the NE Atlantic have been studied: MD95-2006 (Barra Fan; 57°01.82 N, 10°03.48 W; 2120 m water depth) and MD04-2822 (Rockall Trough; 56°50.54 N, 11°22.96 W; 2344 m water depth). The records are anchored to the NGRIP ice core stratigr......Two high resolution marine sediment cores located 83 km apart in the NE Atlantic have been studied: MD95-2006 (Barra Fan; 57°01.82 N, 10°03.48 W; 2120 m water depth) and MD04-2822 (Rockall Trough; 56°50.54 N, 11°22.96 W; 2344 m water depth). The records are anchored to the NGRIP ice core...

  2. Fit for print: developing an institutional model of scientific periodical publishing in England, 1665–ca. 1714

    Science.gov (United States)

    Moxham, N.

    2015-01-01

    This paper explores the contested afterlife of Philosophical Transactions following the death of its founder, Henry Oldenburg. It investigates the complex interrelation between the institution and the periodical at a time when the latter was supposedly independent, and outlines the competing proposals for institutional publishing in science contemplated in the Royal Society, linking some publications that were actually attempted to those proposals and to the Society's attempts to revitalize its experimental programme between 1677 and 1687. It argues that the Society was concerned to produce experimental natural knowledge over which it could claim ownership, and intended this work for publication in other venues than Transactions, whereas the periodical was seen as a more suitable site for work reported to the Society than for research that the institution had primarily produced. It was only from the early 1690s, after the collapse of the Society's experimental programme, that Transactions gradually became a more straightforward reflection of the mainstream of Royal Society activity, paving the way for its formal reinvention as the official publication of the Society in 1752. PMID:26495576

  3. Periodic DFT study of acidic trace atmospheric gas molecule adsorption on Ca and Fe doped MgO (001) surface basic sites

    Science.gov (United States)

    Hatch, Courtney; Orlando, Roberto

    2012-01-01

    The electronic properties of undoped and Ca or Fe doped MgO (001) surfaces, as well as their propensity towards atmospheric acidic gas (CO2, SO2 and NO2) uptake was investigated with an emphasis on gas adsorption on the basic MgO oxygen surface sites, Osurf, using periodic Density Functional Theory (DFT) calculations. Adsorption energy calculations show that MgO doping will provide stronger interactions of the adsorbate with the Osurf sites than the undoped MgO for a given adsorbate molecule. Charge transfer from the iron atom in Fe doped MgO (001) to NO2 was shown to increase the binding interaction between adsorbate by an order of magnitude, when compared to that of undoped and Ca doped MgO (001) surfaces. Secondary binding interactions of adsorbate oxygen atoms were observed with surface magnesium sites at distances close to those of the Mg-O bond within the crystal. These interactions may serve as a preliminary step for adsorption and facilitate further adsorbate transformations into other binding configurations. Impacts on global atmospheric chemistry are discussed as these adsorption phenomena can affect atmospheric gas budgets via altered partitioning and retention on mineral aerosol surfaces. PMID:22775293

  4. Aerosol properties associated with air masses arriving into the North East Atlantic during the 2008 Mace Head EUCAARI intensive observing period: an overview

    Directory of Open Access Journals (Sweden)

    M. Dall'Osto

    2010-09-01

    Full Text Available As part of the EUCAARI Intensive Observing Period, a 4-week campaign to measure aerosol physical, chemical and optical properties, atmospheric structure, and cloud microphysics was conducted from mid-May to mid-June, 2008 at the Mace Head Atmospheric Research Station, located at the interface of Western Europe and the N. E. Atlantic and centered on the west Irish coastline. During the campaign, continental air masses comprising both young and aged continental plumes were encountered, along with polar, Arctic and tropical air masses. Polluted-continental aerosol concentrations were of the order of 3000 cm−3, while background marine air aerosol concentrations were between 400–600 cm−3. The highest marine air concentrations occurred in polar air masses in which a 15 nm nucleation mode, with concentration of 1100 cm−3, was observed and attributed to open ocean particle formation. Continental air submicron chemical composition (excluding refractory sea salt was dominated by organic matter, closely followed by sulphate mass. Although the concentrations and size distribution spectral shape were almost identical for the young and aged continental cases, hygroscopic growth factors (GF and cloud condensation nuclei (CCN to total condensation nuclei (CN concentration ratios were significantly less in the younger pollution plume, indicating a more oxidized organic component to the aged continental plume. The difference in chemical composition and hygroscopic growth factor appear to result in a 40–50% impact on aerosol scattering coefficients and Aerosol Optical Depth, despite almost identical aerosol microphysical properties in both cases, with the higher values been recorded for the more aged case. For the CCN/CN ratio, the highest ratios were seen in the more age plume. In marine air, sulphate mass dominated the sub-micron component, followed by water soluble organic carbon, which, in turn, was dominated by

  5. The influence of Greenland ice sheet melting on the Atlantic meridional overturning circulation during past and future warm periods: a model study

    NARCIS (Netherlands)

    Blaschek, M.; Bakker, P.; Renssen, H.

    2014-01-01

    The sensitivity of the climate system to changes in radiative forcing is crucial for our understanding of past and future climates. Especially important are feedbacks related to melting of ice sheets like the Greenland ice sheet (GIS) and its potential impact on the Atlantic meridional overturning

  6. Data for evaluating the Sr/Ca temperature proxy with in-situ temperature in the western Atlantic coral Siderastrea siderea

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Massive corals are used as environmental recorders throughout the tropics and subtropics to study environmental variability during time periods preceding...

  7. Performance of seven criteria to assess CA125 increments among ovarian cancer patients monitored during first-line chemotherapy and the post-therapy follow-up period

    DEFF Research Database (Denmark)

    Abu Hassan, Suher O; Nielsen, Dorte L; Tuxen, Malgorzata K

    2017-01-01

    AIM: To investigate seven CA125 criteria to monitor progressive ovarian cancer among patients with stage IC-IV disease. MATERIALS & METHODS: Four criteria were used to asses CA125 increments starting from concentrations ≥35 U/ml and three criteria to asses increments starting from concentrations...... U/ml. RESULTS: A total of 231 patients were allocated to CA125 monitoring. The performances of the CA125 criteria were similar with sensitivities of 30-55%, negative predictive values of 28-46%, positive predictive values of 90-100% and median lead times of 26-87 days. CONCLUSION: The criteria...

  8. Correlation of Ice-Rafted Detritus in South Atlantic Sediments with Climate Proxies in Polar Ice over the Last Glacial Period

    Directory of Open Access Journals (Sweden)

    Sharon L. Kanfoush

    2013-03-01

    Full Text Available Previous study identified 6–7 millennial-scale episodes of South Atlantic ice-rafted sediment deposition (SA events during the glaciation. Questions remain, however, regarding their origin, significance for sea-ice and/or Antarctic ice-sheet dynamics, and relationship to climate. Here I correlate sediment core (TTN057–21 SA events to Greenland and Antarctic ice using two independent methods, stable isotopes and geomagnetic paleointensity, placing SA events in the context of polar climate change in both hemispheres. Marine isotopic stage (MIS 3 SA events generally coincided with Greenland interstadials and with cooling following Antarctic warm events (A1-A4. This anti-phase behavior is best illustrated when SA0 coincided with both the Antarctic Cold Reversal and Bolling-Allerod warming in Greenland. Moreover, SA events coincide with sea-level rises during the deglaciation (mwp1A and MIS 3 (30.4, 38.3, 43.7, 51.5 ka, implying unpinning of grounded Weddell Sea region ice masses discharged debris-laden bergs that had a chilling effect on South Atlantic surface temperatures.

  9. Species Profiles. Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates (North Atlantic). Atlantic Herring,

    Science.gov (United States)

    1986-04-01

    Service, Woods Hole, Massachusetts, for reviewing the manuscript. vi Figure 1. Atlantic herring (Clupea harengus L.). ATLANTIC HERRING NOMENCLATURE...extensively reviewed by Svetividov Scales between gill openings and (1952). caudal base ca. 56-62; ventral scutes Preferred common name . Atlantic...summer, 7 A AL and cladocerans in summer and autumn Ann - Jeffreys Ledge area in winter (Sherman and Perkins 1971). (Creaser and Libby 1982). Adults Food

  10. The role of Atlantic overturning circulation in the recent decline of Atlantic major hurricane frequency.

    Science.gov (United States)

    Yan, Xiaoqin; Zhang, Rong; Knutson, Thomas R

    2017-11-22

    Observed Atlantic major hurricane frequency has exhibited pronounced multidecadal variability since the 1940s. However, the cause of this variability is debated. Using observations and a coupled earth system model (GFDL-ESM2G), here we show that the decline of the Atlantic major hurricane frequency during 2005-2015 is associated with a weakening of the Atlantic Meridional Overturning Circulation (AMOC) inferred from ocean observations. Directly observed North Atlantic sulfate aerosol optical depth has not increased (but shows a modest decline) over this period, suggesting the decline of the Atlantic major hurricane frequency during 2005-2015 is not likely due to recent changes in anthropogenic sulfate aerosols. Instead, we find coherent multidecadal variations involving the inferred AMOC and Atlantic major hurricane frequency, along with indices of Atlantic Multidecadal Variability and inverted vertical wind shear. Our results provide evidence for an important role of the AMOC in the recent decline of Atlantic major hurricane frequency.

  11. Millennial-scale climate variability in the south-eastern North America and the subtropical North Atlantic during the last glacial period: a land-sea correlation derived from the pollen rich marine core MD99-2203

    Science.gov (United States)

    Lopez-Martinez, C.; Sanchez Goñi, M. F.; Desprat, S.; Rossignol, L.

    2009-04-01

    Last glacial abrupt climate changes, defined as Dansgaard/Oeschger variability (D/O) and Heinrich events (HE), have been documented in ice cores, marine sediments and continental deposits, generally from the Northern Hemisphere (Voelker et al., 2002). While most North Atlantic paleoceanographic and paleoclimatic studies covering the last glacial period are centred in the northern and eastern part (Voelker et al., 2002), less attention has been paid to the western midlatitudes (López-Martínez et al., 2006; Vautravers et al., 2004). In particular last glacial eastern North American vegetation changes remain poorly unknown due to a lack of long continuous pollen records in this region. So far, only two pollen sequences from Lake Tulane (Florida) show significant and interesting vegetation changes during the last glacial period (Grimm et al., 1993 and 2006) which suggest warm and humid HE, contrasting with what is observed in the eastern part of the North Atlantic (Sánchez Goñi et al., 2000). In this work we present the first high resolution reconstruction of the vegetation changes derived from the analysis of a pollen-rich marine core located in the subtropical western North Atlantic (MD99-2203, 34°58'N, 75°12'W, 620 m water depth) during Marine Isotope Stage 3 (MIS3). A clear alternation between Picea and Quercus is showed by pollen data from core MD99-2203. In general, pollen assemblages indicate last glacial vegetation variations following a boreal forest/mesic-Quercus forest pattern that could be associated with the D/O variability. A preliminary age model based on radiocarbon ages suggests an increase of temperate forest accompanied by a reduction of the boreal forest during Greenland interstadials (López-Martínez et al., in preparation). Comparison with other proxies measured in the same core (d18O and alkenone and planktonic foraminifera derived sea surface temperature) and with published high resolution marine pollen records from the eastern

  12. Sea Surface Temperature Reconstruction Period 1993 - 2007 Based on Content Analysis of Coral Sr/Ca from the Region Labuan Bajo, Simeulue Island

    Directory of Open Access Journals (Sweden)

    Sri Yudawati Cahyarini

    2014-06-01

    Full Text Available DOI: 10.17014/ijog.v6i3.121Sea surface temperature (SST is one of the important parameters for (paleo climate studies. The long time series of SST data are required to understand more the climate change. Coral geochemical proxy such as Sr/Ca overcomes this problem. Coral can provide long time series of climate data continuously from present till hundreds years ago, even fossil (dead coral can do it till thousand years ago. In this study, Sr/Ca content of Porites coral within 10 m deep from Labuan Bajo, Simeulue Island was analyzed to reconstruct SST. Coral Sr/Ca shows a strong correlation with local SST in seasonal scale as well as in the annual mean scale. Reconstructed SST data show that the monsoon between 1993 2007 strongly influence the SST variation in the Simeulue region. It supposed that the seasonal variation signal strongly influence local SST than the annual mean signal such as El Nino.

  13. Ability of an ensemble of regional climate models to reproduce weather regimes over Europe-Atlantic during the period 1961-2000

    Energy Technology Data Exchange (ETDEWEB)

    Somot, S.; Deque, M. [Meteo-France CNRM/GMGEC CNRS/GAME, Toulouse (France); Sanchez-Gomez, Emilia

    2009-10-15

    One of the main concerns in regional climate modeling is to which extent limited-area regional climate models (RCM) reproduce the large-scale atmospheric conditions of their driving general circulation model (GCM). In this work we investigate the ability of a multi-model ensemble of regional climate simulations to reproduce the large-scale weather regimes of the driving conditions. The ensemble consists of a set of 13 RCMs on a European domain, driven at their lateral boundaries by the ERA40 reanalysis for the time period 1961-2000. Two sets of experiments have been completed with horizontal resolutions of 50 and 25 km, respectively. The spectral nudging technique has been applied to one of the models within the ensemble. The RCMs reproduce the weather regimes behavior in terms of composite pattern, mean frequency of occurrence and persistence reasonably well. The models also simulate well the long-term trends and the inter-annual variability of the frequency of occurrence. However, there is a non-negligible spread among the models which is stronger in summer than in winter. This spread is due to two reasons: (1) we are dealing with different models and (2) each RCM produces an internal variability. As far as the day-to-day weather regime history is concerned, the ensemble shows large discrepancies. At daily time scale, the model spread has also a seasonal dependence, being stronger in summer than in winter. Results also show that the spectral nudging technique improves the model performance in reproducing the large-scale of the driving field. In addition, the impact of increasing the number of grid points has been addressed by comparing the 25 and 50 km experiments. We show that the horizontal resolution does not affect significantly the model performance for large-scale circulation. (orig.)

  14. On One-Sided, D-Chaotic CA Without Fixed Points, Having Continuum of Periodic Points With Period 2 and Topological Entropy log(p for Any Prime p

    Directory of Open Access Journals (Sweden)

    Wit Forys

    2014-10-01

    Full Text Available A method is known by which any integer \\(\\, n\\geq2\\,\\ in a metric Cantor space of right-infinite words \\(\\,\\tilde{A}_{n}^{\\,\\mathbb N}\\,\\ gives a construction of a non-injective cellular automaton \\(\\,(\\tilde{A}_{n}^{\\,\\mathbb N},\\,\\tilde{F}_{n},\\,\\ which is chaotic in Devaney sense, has a radius \\(\\, r=1,\\,\\ continuum of fixed points and topological entropy \\(\\, log(n.\\,\\ As a generalization of this method we present for any integer \\(\\, n\\geq2,\\,\\ a construction of a cellular automaton \\(\\,(A_{n}^{\\,\\mathbb{N}},\\, F_{n},\\,\\ which has the listed properties of \\(\\,(\\tilde{A}_{n}^{\\,\\mathbb N},\\,\\tilde{F}_{n},\\,\\ but has no fixed points and has continuum of periodic points with the period 2. The construction is based on properties of cellular automaton introduced here \\(\\,(B^{\\,\\mathbb N},\\, F\\,\\ with radius \\(1\\ defined for any prime number \\(\\, p.\\,\\ We prove that \\(\\,(B^{\\,\\mathbb N},\\, F\\,\\ is non-injective, chaotic in Devaney sense, has no fixed points, has continuum of periodic points with the period \\(2\\ and topological entropy \\(\\, log(p.\\,\\

  15. Variability of Mg/Ca and Sr/Ca between and within the planktonic foraminifers Globigerina bulloides and Globorotalia truncatulinoides

    NARCIS (Netherlands)

    Anand-Jha, P.; Elderfield, H.

    2005-01-01

    The variability in Mg/Ca and Sr/Ca within individual tests and chambers of tests, and samples consisting of differing numbers of individuals, was determined for Globigerina bulloides and Globorotalia truncatulinoides in a North Atlantic core top sample (52.918°N 16.917°W'). The variability in Mg/Ca

  16. Constraining the mechanisms driving coccolith δ44/40Ca and Sr/Ca variations: new perspectives from cultures, cellular models, and the sediment record

    Science.gov (United States)

    María Mejía, Luz; Paytan, Adina; Eisenhauer, Anton; Kolevica, Ana; Bolton, Clara; Méndez-Vicente, Ana; Abrevaya, Lorena; Isensee, Kirsten; Stoll, Heather

    2017-04-01

    Coccoliths comprise a major fraction of the calcium carbonate (CaCO3) production, with contributions varying from 95% of the global carbonate sink during the Cenozoic, to 50% in the modern ocean. Therefore, significant changes in coccolith Ca isotopic fractionation could have affected past seawater Ca isotopic composition (δ44/40Ca), with potential important implications for the interpretation of the global Ca cycle and related changes in seawater chemistry. Here we evaluate the mechanisms driving coccolith Ca isotopic fractionation in a quantitative framework, by deriving a steady-state mass balance geochemical model (CaSri-Co), which assumes that fractionation is solely associated with desolvation (i.e. dehydration) of Ca during cellular transport through membranes. The application of the CaSri-Co model to previously published and to our new δ44/40Ca and Sr/Ca results from cultured coccolithophores (Emiliania huxleyi, Gephyrocapsa oceanica and Calcidiscus leptoporus) allowed us to identify calcification rates, Ca retention efficiency and water structure strength as main regulators of the Ca isotopic fractionation and Sr/Ca ratios of cultured coccolith calcite. Higher calcification rates, higher Ca retention efficiencies and higher water structure strength (slower Ca solvation-desolvation reactions) increase both coccolith Sr/Ca and Ca isotopic fractionation. The CaSri-Co model shows that coccolith Ca isotopic fractionation is especially sensitive to changes in water structure strength. On the other hand, Ca retention efficiency appears to be the main driver of the observed Sr/Ca trends, which results from the incomplete usage of the Sr transported to the calcification vesicle and subsequent Sr enrichment of the cytosol, while Ca inside the calcification vesicle is assumed to be completely utilized in the model. In this study we also measured δ44/40Ca and Sr/Ca in two coccolith size fraction from site 925 in the Western Equatorial Atlantic representing the last

  17. The role of Atlantic-Arctic exchange in North Atlantic multidecadal climate variability

    NARCIS (Netherlands)

    Frankcombe, L.M.|info:eu-repo/dai/nl/304829838; Dijkstra, H.A.|info:eu-repo/dai/nl/073504467

    2011-01-01

    It has recently been suggested that multidecadal variability in North Atlantic sea surface temperature occurs with two dominant periods. In this paper we investigate the origin of these two time scales in a 500 year control run of the GFDL CM2.1 model. We focus on the exchange between the Atlantic

  18. 2005 Atlantic Hurricanes Poster

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The 2005 Atlantic Hurricanes poster features high quality satellite images of 15 hurricanes which formed in the Atlantic Basin (includes Gulf of Mexico and Caribbean...

  19. South Atlantic Shrimp System

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The SEFSC, in cooperation with the South Atlantic states, collects South Atlantic shrimp data from dealers and fishermen. These data are collected to provide catch,...

  20. The potential of the coral species Porites astreoides as a paleoclimate archive for the Tropical South Atlantic Ocean

    Science.gov (United States)

    Pereira, N. S.; Sial, A. N.; Frei, R.; Ullmann, C. V.; Korte, C.; Kikuchi, R. K. P.; Ferreira, V. P.; Kilbourne, K. H.

    2017-08-01

    The aragonitic skeletons of corals are unique archives of geochemical tracers that can be used as proxies for environmental conditions with high fidelity and sub-annual resolution. Such records have been extensively used for reconstruction of climatic conditions in the Pacific and Indian Oceans, Red Sea and Caribbean, but lack for the Equatorial South Atlantic. Here we present coral-based records of Sr/Ca, δ18O and δ13C and the first δ18O-SST calibration for the scleractinian coral species Porites astreoides from the Rocas Atoll, Equatorial South Atlantic. The investigated geochemical proxies for P. astreoides presented a very well-developed seasonal cyclicity in all proxies. We use the monthly means of δ18O and SST from the period of 2001-2013 to propose a calibration for a paleothermometer based on Porites, which gives T(°C) = -8.69(±0.79)* δ18O -7.05(±3.14), and yielded a SST δ18O-depended reconstruction with fidelity better than 0.5 °C for most of the record. Biases of up to 2 °C might be associated with reduced growth rate periods of the coral record. The Sr/Ca data show systematic, annual fluctuations but analyses are too imprecise to propose a Sr/Ca-SST calibration. The δ13C values are found to vary in phase with δ18O and Sr/Ca and are interpreted to be controlled by solar irradiation-modulated photosynthetic activity on the annual level. Our findings extend the global data base of coral records, contributing to further investigations using coral skeleton as environmental archives. In particular, the present study helps to better understand the climate variability of the South Atlantic tropical ocean-atmosphere system.

  1. Blue whale (Balaenoptera musculus) sounds from the North Atlantic

    Science.gov (United States)

    Mellinger, David K.; Clark, Christopher W.

    2003-08-01

    Sounds of blue whales were recorded from U.S. Navy hydrophone arrays in the North Atlantic. The most common signals were long, patterned sequences of very-low-frequency sounds in the 15-20 Hz band. Sounds within a sequence were hierarchically organized into phrases consisting of one or two different sound types. Sequences were typically composed of two-part phrases repeated every 73 s: a constant-frequency tonal ``A'' part lasting approximately 8 s, followed 5 s later by a frequency-modulated ``B'' part lasting approximately 11 s. A common sequence variant consisted only of repetitions of part A. Sequences were separated by silent periods averaging just over four minutes. Two other sound types are described: a 2-5 s tone at 9 Hz, and a 5-7s inflected tone that swept up in frequency to ca. 70 Hz and then rapidly down to 25 Hz. The general characteristics of repeated sequences of simple combinations of long-duration, very-low-frequency sound units repeated every 1-2 min are typical of blue whale sounds recorded in other parts of the world. However, the specific frequency, duration, and repetition interval features of these North Atlantic sounds are different than those reported from other regions, lending further support to the notion that geographically separate blue whale populations have distinctive acoustic displays.

  2. A Low-Li Geochemical Province in the NE Atlantic

    DEFF Research Database (Denmark)

    Bailey, J. C.; Gwozdz, R.

    1978-01-01

    Lithium was analysed in 392 basalts and related igneous rocks from the North Atlantic Tertiary-Recent province using activation analysis and Čerenkov counting. Monotonous Li values of 5.5±2 ppm in NE Atlantic basalts define a low-Li geochemical province which has persisted for 60 million years...... basalt series. No whole-rock coherence is observed between Li and Mg, K, Rb or Ca. Mantle phlogopite is considered to play an insignificant rôle in controlling the Li levels of NE Atlantic basalts....

  3. Spatial and temporal distribution of North Atlantic tropical cyclones ...

    African Journals Online (AJOL)

    month of genesis and their lifecycles and to study the role of African Easterly Waves (AEWs) in North Atlantic cyclogenesis. Between 1980 and 2004, 269 tropical cyclones (TCs) were formed over the North Atlantic, 77% of which occurred during the August-October period and 95% of major hurricanes (TCs in which the ...

  4. Late Holocene climate change in the western Mediterranean: centennial-scale vegetation and North Atlantic Oscillation variability

    Science.gov (United States)

    Ramos Román, M. J.; Jimenez-Moreno, G.; Anderson, R. S.; García-Alix, A.; Toney, J. L.; Jiménez-Espejo, F. J. J.; Carrión, J. S.

    2015-12-01

    Sediments from alpine peat bogs and lakes from the Sierra Nevada in southeastern Spain (western Mediterranean area) have been very informative in terms of how vegetation and wetland environments were impacted by past climate change. Recently, many studies try to find out the relationship between solar activity, atmosphere and ocean dynamics and changes in the terrestrial environments. The Mediterranean is a very sensitive area with respect to atmospheric dynamics due to (1) its location, right in the boundary between subtropical and temperate climate systems and (2) the North Atlantic Oscillation (NAO) is one of the main mechanism that influence present climate in this area. Here we present a multi-proxy high-resolution study from Borreguil de la Caldera (BdlC), a peat bog that records the last ca. 4500 cal yr BP of vegetation, fire, human impact and climate history from the Sierra Nevada. The pollen, charcoal and non-pollen palynomorphs (NPPs) reconstruction in the BdlC-01 record evidence relative humidity changes in the last millennia interrupting the late Holocene aridification trend. This study shows a relative arid period between ca. 4000 and 3100 cal yr BP; the Iberian Roman humid period (ca. 2600 to 1600 cal yr BP); a relative arid period during the Dark Ages (from ca. AD 500 to AD 900) and Medieval Climate Anomaly (from ca. AD 900 to ca. AD 1300) and predominantly wetter conditions corresponding with The Little Ice Age period (from ca. AD 1300 to AD 1850). This climate variability could be explained by centennial scale changes in the NAO and solar activity.

  5. Evidence of multidecadal climate variability and the Atlantic Multidecadal Oscillation from a Gulf of Mexico sea-surface temperature-proxy record

    Science.gov (United States)

    Poore, R.Z.; DeLong, K.L.; Richey, J.N.; Quinn, T.M.

    2009-01-01

    A comparison of a Mg/Ca-based sea-surface temperature (SST)-anomaly record from the northern Gulf of Mexico, a calculated index of variability in observed North Atlantic SST known as the Atlantic Multidecadal Oscillation (AMO), and a tree-ring reconstruction of the AMO contain similar patterns of variation over the last 110 years. Thus, the multidecadal variability observed in the instrumental record is present in the tree-ring and Mg/Ca proxy data. Frequency analysis of the Gulf of Mexico SST record and the tree-ring AMO reconstruction from 1550 to 1990 found similar multidecadal-scale periodicities (???30-60 years). This multidecadal periodicity is about half the observed (60-80 years) variability identified in the AMO for the 20th century. The historical records of hurricane landfalls reveal increased landfalls in the Gulf Coast region during time intervals when the AMO index is positive (warmer SST), and decreased landfalls when the AMO index is negative (cooler SST). Thus, we conclude that alternating intervals of high and low hurricane landfall occurrences may continue on multidecadal timescales along the northern Gulf Coast. However, given the short length of the instrumental record, the actual frequency and stability of the AMO are uncertain, and additional AMO proxy records are needed to establish the character of multidecadal-scale SST variability in the North Atlantic. ?? 2009 US Government.

  6. Variable water column structure of the South Atlantic on glacial-interglacial time scales

    Science.gov (United States)

    Martínez-Méndez, Gema; Molyneux, Elizabeth G.; Hall, Ian R.; Zahn, Rainer

    2009-12-01

    The structure of the glacial ocean was significantly different to that of the present day with intermediate to mid-depth waters being notably more δ 13C enriched than deep waters. This contrast was especially pronounced in the South Atlantic suggesting the development of a sharp chemical divide, or 'chemocline', at around 2500 m water depth between upper and lower layers, with implications for deep-ocean carbon storage [ Hodell et al., 2003. Pleistocene vertical carbon isotope and carbonate gradients in the South Atlantic sector of the Southern Ocean. Geochemistry, Geophysics, Geosystems, 4(1): doi: 1004 10.1029/2002GC000367.]. We evaluate existing benthic foraminiferal δ 13C, Cd/Ca and derived carbon isotope air-sea exchange signature (δ 13C as) data sets for the Atlantic during the Last Glacial Maximum (LGM), and Marine Isotope Stages (MIS) 6 and 8 in order to examine the regional extent of the chemocline in the South Atlantic. Benthic δ 13C data north of the approximate latitude of the LGM Subantarctic Front (LGM-SAF, 43°S) linearly decrease with water depth, indicative of mixing between upper 'well' and lower 'poorly' ventilated water masses, with little evidence of the sharp chemical divide. Conversely, benthic δ 13C data south of the LGM-SAF below 2500 m water depth are uniformly around -0.8‰. The apparent δ 13C gradient across the LGM-SAF suggests enhanced mid-depth ventilation north of the SAF and reduced ventilation to the south. From this pattern we conclude that the regional chemocline in the South Atlantic constituted a dominantly meridional, rather than a vertical gradient, and was developed during at least the past three glacial periods. Benthic Cd/Ca data indicate that the gradient was not nutrient related, although further data from the South Atlantic are needed for a better assessment of this suggestion. The combined benthic δ 13C and Cd/Ca data indicate the source of well-ventilated upper waters in the South Atlantic changed from

  7. Climate Prediction Center (CPC) East Atlantic Teleconnection Pattern Index

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Monthly tabulated index of the East Atlantic Teleconnection pattern. The data spans the period 1950 to present. The index is derived from a rotated principal...

  8. The potential of the coral species Porites astreoides as a paleoclimate archive for the Tropical South Atlantic Ocean

    DEFF Research Database (Denmark)

    Pereira, Natan S.; Sial, Alcides N.; Frei, Robert

    2017-01-01

    The aragonitic skeletons of corals are unique archives of geochemical tracers that can be used as proxies for environmental conditions with high fidelity and sub-annual resolution. Such records have been extensively used for reconstruction of climatic conditions in the Pacific and Indian Oceans......, Red Sea and Caribbean, but lack for the Equatorial South Atlantic. Here we present coral-based records of Sr/Ca, δ18O and δ13C and the first δ18O–SST calibration for the scleractinian coral species Porites astreoides from the Rocas Atoll, Equatorial South Atlantic. The investigated geochemical proxies......–depended reconstruction with fidelity better than 0.5 °C for most of the record. Biases of up to 2 °C might be associated with reduced growth rate periods of the coral record. The Sr/Ca data show systematic, annual fluctuations but analyses are too imprecise to propose a Sr/Ca-SST calibration. The δ13C values are found...

  9. Atlantic Salmon Telemetry Monitoring

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Annual telemetry data are collected as part of specific projects (assessments within watersheds) or as opportunistic efforts to characterize Atlantic salmon smolt...

  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. Thermohaline circulation in the North Atlantic and its simulation with a box model

    Science.gov (United States)

    Averyanova, E. A.; Polonsky, A. B.; Sannikov, V. F.

    2017-05-01

    Features of the North Atlantic thermohaline circulation response to periodic, stochastic, and instantaneous forcing are studied using a four-box model. The present-day circulation is shown to be characterized by a stable quasi-periodic oscillatory mode that manifests itself as the Atlantic Multidecadal Oscillation. The thermohaline catastrophe is unlikely in the modern climate epoch.

  12. Hippocampal epileptiform activity induced by magnesium-free medium: differences between areas CA1 and CA2-3.

    Science.gov (United States)

    Lewis, D V; Jones, L S; Mott, D D

    1990-07-01

    Hippocampal slices, from which the entorhinal cortex had been removed, were exposed to artificial cerebrospinal fluid containing no magnesium (0-Mg ACSF) to elicit interictal bursts (IIBs) and electrographic seizures (EGSs). In 0-Mg ACSF, IIBs and EGSs occurred in both area CA1 and area CA3. The IIBs in CA3 led the IIBs in CA1 by several milliseconds. The epileptiform bursts occurring during the EGSs seemed to have the opposite relationship, with bursts in CA1 leading those in CA3 by several milliseconds. When the connections between CA1 and CA2-3 were cut, the IIBs ceased in CA1 and continued in CA3. To further characterize the local differences in epileptiform activity, totally separate minislices of area CA1 and area CA2-3 were prepared. In the CA2-3 minislices, a few EGSs occurred and thereafter only persistent IIBs prevailed. Conversely, in the CA1 minislices, many spontaneous EGSs occurred for long periods of time and no IIBs were seen. Periodic stimulation of the CA1 minislices triggered IIBs that suppressed the recurrent EGSs. In the hippocampal slice exposed to low magnesium, IIBs originate in CA2-3 and are propagated to CA1, where they can have a suppressant effect on EGSs. Furthermore, unlike IIBs, the bursts making up the EGSs seem to start in CA1 and invade CA2-3.

  13. Atlantic menhaden adult tagging study

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Atlantic menhaden are a schooling forage fish species, which are subject to a large commercial purse seine fishery. Atlantic menhaden are harvested for reduction...

  14. Periodic Mesoporous Organosilica Nanorice

    Directory of Open Access Journals (Sweden)

    Mohanty Paritosh

    2008-01-01

    Full Text Available Abstract A periodic mesoporous organosilica (PMO with nanorice morphology was successfully synthesized by a template assisted sol–gel method using a chain-type precursor. The PMO is composed of D and T sites in the ratio 1:2. The obtained mesoporous nanorice has a surface area of 753 m2 g−1, one-dimensional channels, and a narrow pore size distribution centered at 4.3 nm. The nanorice particles have a length of ca. 600 nm and width of ca. 200 nm.

  15. Coccolithophore surface distributions in the North Atlantic and their modulation of the air-sea flux of CO2 from 10 years of satellite Earth observation data

    Directory of Open Access Journals (Sweden)

    J. D. Shutler

    2013-04-01

    Full Text Available Coccolithophores are the primary oceanic phytoplankton responsible for the production of calcium carbonate (CaCO3. These climatically important plankton play a key role in the oceanic carbon cycle as a major contributor of carbon to the open ocean carbonate pump (~50% and their calcification can affect the atmosphere-to-ocean (air-sea uptake of carbon dioxide (CO2 through increasing the seawater partial pressure of CO2 (pCO2. Here we document variations in the areal extent of surface blooms of the globally important coccolithophore, Emiliania huxleyi, in the North Atlantic over a 10-year period (1998–2007, using Earth observation data from the Sea-viewing Wide Field-of-view Sensor (SeaWiFS. We calculate the annual mean sea surface areal coverage of E. huxleyi in the North Atlantic to be 474 000 ± 104 000 km2, which results in a net CaCO3 carbon (CaCO3-C production of 0.14–1.71 Tg CaCO3-C per year. However, this surface coverage (and, thus, net production can fluctuate inter-annually by −54/+8% about the mean value and is strongly correlated with the El Niño/Southern Oscillation (ENSO climate oscillation index (r=0.75, pE. huxleyi blooms in the North Atlantic can increase the pCO2 and, thus, decrease the localised air-sea flux of atmospheric CO2. In regions where the blooms are prevalent, the average reduction in the monthly air-sea CO2 flux can reach 55%. The maximum reduction of the monthly air-sea CO2 flux in the time series is 155%. This work suggests that the high variability, frequency and distribution of these calcifying plankton and their impact on pCO2 should be considered if we are to fully understand the variability of the North Atlantic air-to-sea flux of CO2. We estimate that these blooms can reduce the annual N. Atlantic net sink atmospheric CO2 by between 3–28%.

  16. Palaeoceanographic productivity changes in the Eastern Equatorial Atlantic since the penultimate glaciation

    Science.gov (United States)

    Lem, Rachael; Marshall, Jim; Leng, Melanie; Marret, Fabienne

    2017-04-01

    A 150,000 year multiproxy record from the eastern equatorial Atlantic, offshore Gabon, has been investigated in order to examine the effects of changing glacial - interglacial climate on marine productivity. Higher δ13C values of the benthic foraminifera Planulina wuellerstorfi are documented during the penultimate glaciation (150 -130 kyr BP) in comparison to the Last Glacial Maximum [LGM] (24.5 - 19 kyr BP). In conjunction with higher CaCO3 and larger variability in the isotopic difference between surface and bottom waters during the penultimate glaciation, this suggests that the eastern equatorial Atlantic was much more productive at this time than the LGM, most likely driven by increased nutrient input through strong bottom water upwelling. The benthic δ18O and planktonic δ18O record of Globigerinoides ruber (white) infer that both the surface and bottom waters were warmer during the penultimate glaciation than the LGM. The sea surface temperature [SST] record assimilated through Mg/Ca analysis of the G. ruber evidences much lower SSTs during the last deglaciation in comparison with other regional records, and with the present day SST, which together with high Fe input, we attribute this to a greatly enhanced discharge of the Ogooué River. Bulk coccolith carbonate δ13C demonstrates a shift towards lower δ13C values from the penultimate glaciation towards present day which does not dovetail the other proxies. The δ18O coccolith record mirrors that of G. ruber during the two glacial periods, but presents much higher isotopic values during the interglacials. We interpret this as a shift in seasonality in the calcification of the coccoliths between glacial and interglacial periods, which in combination with the long term decline in δ13C values reflects a change in the habitat preferences of this phytoplankton over the last glacial - interglacial cycle.

  17. 75 FR 11129 - Mid-Atlantic Fishery Management Council; Atlantic Mackerel, Butterfish, Atlantic Bluefish, Spiny...

    Science.gov (United States)

    2010-03-10

    ... ; Mail or hand deliver to Daniel T. Furlong, Executive Director, Mid-Atlantic Fishery Management Council... Council by telephone (302) 674-2331. FOR FURTHER INFORMATION CONTACT: Mr. Daniel T. Furlong, Mid-Atlantic...

  18. Response of North Atlantic Ocean Chlorophyll a to the Change of Atlantic Meridional Overturning Circulation

    Science.gov (United States)

    Zhang, Min; Zhang, Yuanling; Shu, Qi; Zhao, Chang; Wang, Gang; Wu, Zhaohua; Qiao, Fangli

    2017-04-01

    Changes in marine phytoplankton are a vital component in global carbon cycling. Despite this far-reaching importance, the variable trend in phytoplankton and its response to climate variability remain unclear. This work presents the spatiotemporal evolution of the chlorophyll a trend in the North Atlantic Ocean by using merged ocean color products for the period 1997-2016. We find a dipole pattern between the subpolar gyre and the Gulf Stream path,and chlorophyll a trend signal propagatedalong the opposite direction of the North Atlantic Current. Such a dipole pattern and opposite propagation of chlorophyll a signal are consistent with the recent distinctive signature of the slowdown of the Atlantic MeridionalOverturning Circulation (AMOC). It is suggested that the spatiotemporal evolution of chlorophyll a during the two most recent decades is a part of the multidecadal variation and regulated byAMOC, which could be used as an indicator of AMOC variations.

  19. Regulatory volume response following hypotonic stress in Atlantic salmon erythrocytes.

    Science.gov (United States)

    Wormser, Chloe; Mason, Louise Z; Helm, Ethan M; Light, Douglas B

    2011-12-01

    The purpose of this study was to examine regulatory volume decrease (RVD) in Atlantic salmon red blood cells (RBCs). Osmotic fragility was determined optically, mean cell volume was measured electronically, and changes in intracellular Ca(2+) concentration were visualized using fluorescence microscopy and fluo-4-AM. Cells displayed an increase in osmotic fragility and an inhibition of volume recovery following hypotonic shock when they were exposed to a high taurine Ringer or when placed in a high K(+) medium. Interestingly, RVD in cells from fish collected during the summer depended more on taurine efflux, whereas fall cells relied more on the loss of K(+). In addition, RVD in fall cells was prevented with the K(+) channel inhibitor quinine, whereas the ionophore gramicidin decreased osmotic fragility and potentiated volume recovery. Further, hypotonic shock (0.5X Ringer) for both summer and fall cells caused an increase in cytosolic Ca(2+), which resulted from influx of this ion because it was not observed when extracellular Ca(2+) was chelated with EGTA (10 nM free Ca(2+)). Cells exposed to a low Ca(2+) hypotonic Ringer also had a greater osmotic fragility and failed to recover from hypotonic swelling. Finally, inhibition of phospholipase A(2) with ONO-RS-082 blocked volume recovery. In conclusion, Atlantic salmon RBCs displayed volume decrease in response to hypotonic shock, which depended on a swelling-induced influx of Ca(2+) and an increase in the efflux of K(+) and taurine.

  20. Cenozoic uplift and subsidence in the North Atlantic region

    DEFF Research Database (Denmark)

    Anell, Ingrid Anna Margareta; Thybo, Hans; Artemieva, Irina

    2009-01-01

    , time and amplitude (where possible) of topographic changes in the North Atlantic region during the Cenozoic (65-0 Ma). Our compilation is based on published results from reflection seismic studies, AFT (apatite fission track) studies, VR (vitrinite reflectance) trends, maximum burial, sediment supply...... studies, mass balance calculations and extrapolation of seismic profiles to onshore geomorphological features. The integration of about 200 published results reveal a clear pattern of topographic changes in the North Atlantic region during the Cenozoic: (1) The first major phase of Cenozoic regional...... uplift occurred in the late Palaeocene-early Eocene (ca 60-50 Ma), probably related to the break-up of the North Atlantic between Europe and Greenland, as indicated by the northward propagation of uplift. It was preceded by middle Palaeocene uplift and over-deepening of some basins of the North Sea...

  1. Coupling of equatorial Atlantic surface stratification to glacial shifts in the tropical rainbelt.

    Science.gov (United States)

    Portilho-Ramos, R C; Chiessi, C M; Zhang, Y; Mulitza, S; Kucera, M; Siccha, M; Prange, M; Paul, A

    2017-05-08

    The modern state of the Atlantic meridional overturning circulation promotes a northerly maximum of tropical rainfall associated with the Intertropical Convergence Zone (ITCZ). For continental regions, abrupt millennial-scale meridional shifts of this rainbelt are well documented, but the behavior of its oceanic counterpart is unclear due the lack of a robust proxy and high temporal resolution records. Here we show that the Atlantic ITCZ leaves a distinct signature in planktonic foraminifera assemblages. We applied this proxy to investigate the history of the Atlantic ITCZ for the last 30,000 years based on two high temporal resolution records from the western Atlantic Ocean. Our reconstruction indicates that the shallowest mixed layer associated with the Atlantic ITCZ unambiguously shifted meridionally in response to changes in the strength of the Atlantic meridional overturning with a southward displacement during Heinrich Stadials 2-1 and the Younger Dryas. We conclude that the Atlantic ITCZ was located at ca. 1°S (ca. 5° to the south of its modern annual mean position) during Heinrich Stadial 1. This supports a previous hypothesis, which postulates a southern hemisphere position of the oceanic ITCZ during climatic states with substantially reduced or absent cross-equatorial oceanic meridional heat transport.

  2. 78 FR 59878 - Atlantic Highly Migratory Species; Commercial Atlantic Aggregated Large Coastal Shark (LCS...

    Science.gov (United States)

    2013-09-30

    ... Species; Commercial Atlantic Aggregated Large Coastal Shark (LCS), Atlantic Hammerhead Shark, Atlantic Blacknose Shark, and Atlantic Non-Blacknose Small Coastal Shark (SCS) Management Groups AGENCY: National... hammerhead sharks in the Atlantic region, and blacknose sharks and non-blacknose SCS in the Atlantic region...

  3. A millennium of north-east Atlantic cod juvenile growth trajectories inferred from archaeological otoliths.

    Directory of Open Access Journals (Sweden)

    Guðbjörg Ásta Ólafsdóttir

    Full Text Available Archaeological excavations of historical fishing sites across the North Atlantic have recovered high quantities of Atlantic cod (Gadus morhua bones. In the current study we use Atlantic cod otoliths from archaeological excavations of a historical fishing sites in north-west Iceland, dated to AD 970 -AD 1910 to examine historical growth trajectories of cod. No large scale growth variations or shifts in growth patterns were observed in the current chronologies, supporting the stability of historical Atlantic cod growth trajectories. The most significant variation in growth patterns was consistent with those that have been observed in recent times, for example, reduced early juvenile growth during periods of colder ocean temperature. The current results represent a high resolution chronological record of north-east Atlantic cod growth, greatly increasing the prior temporal range of such data, thereby providing a valuable baseline for a broad range of studies on Atlantic cod growth.

  4. A millennium of north-east Atlantic cod juvenile growth trajectories inferred from archaeological otoliths.

    Science.gov (United States)

    Ólafsdóttir, Guðbjörg Ásta; Pétursdóttir, Gróa; Bárðarson, Hlynur; Edvardsson, Ragnar

    2017-01-01

    Archaeological excavations of historical fishing sites across the North Atlantic have recovered high quantities of Atlantic cod (Gadus morhua) bones. In the current study we use Atlantic cod otoliths from archaeological excavations of a historical fishing sites in north-west Iceland, dated to AD 970 -AD 1910 to examine historical growth trajectories of cod. No large scale growth variations or shifts in growth patterns were observed in the current chronologies, supporting the stability of historical Atlantic cod growth trajectories. The most significant variation in growth patterns was consistent with those that have been observed in recent times, for example, reduced early juvenile growth during periods of colder ocean temperature. The current results represent a high resolution chronological record of north-east Atlantic cod growth, greatly increasing the prior temporal range of such data, thereby providing a valuable baseline for a broad range of studies on Atlantic cod growth.

  5. Atlantic Oceanographic and Meteorological Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The Atlantic Oceanographic and Meteorological Laboratory conducts research to understand the physical, chemical, and biological characteristics and processes of the...

  6. Mechanical Strain Regulates Osteoblast Proliferation Through Ca(2+)-CaMK-CREB Signal Pathway.

    Science.gov (United States)

    Guo, Yong; Lv, Qi; Zou, Xian-Qiong; Yan, Zhi-Xiong; Yan, Yu-Xian

    2016-06-20

    Objective To investigate the effects of mechanical strain on Ca(2+)-calmodulin dependent kinase (CaMK)-cAMP response element binding protein (CREB) signal pathway and proliferation of osteoblasts.Methods Using a four-point bending device, MC3T3-E1 cells were exposed to mechanical tensile strains of 2500 µs and 5000 µs at 0.5 Hz respectively. The intracellular free Ca(2+) ([Ca(2+)]i) concentration and calmodulin activity were assayed by fluorospectrophotometry, CaMK II β, CREB, and phosphorylated (activated) CREB (p-CREB) were assessed by Western blot, and cells proliferation was assayed with MTT. Pretreatment with verapamil was carried out to block Ca(2+) channel, and inhibitor U73122 was used to inhibit phospholipase C (PLC).Results Mechanical strains of 2500 µs and 5000 µs for 1 to 10 minutes both increased [Ca(2+)]i level of the cells. The 2500 µs strain, a periodicity of 1 h/d for 3 days, activated calmodulin, elevated protein levels of CaMK II β and p-CREB, and promoted cells proliferation, which were attenuated by pretreatment of verapamil or U73122. The effects of 5000 µs strain on calmodulin, CaMK II β, p-CREB and proliferation were contrary to 2500 µs strain.Conclusion The mechanical strain regulates osteoblasts proliferation through Ca(2+)-CaMK-CREB signal pathway via Ca(2+) channel and PLC/IP3 transduction cascades.

  7. Recent Decadal Trend in the North Atlantic Wind Energy Resources

    Directory of Open Access Journals (Sweden)

    Chong Wei Zheng

    2017-01-01

    Full Text Available This study presents the climatic trend of the North Atlantic wind energy using cross-calibrated, multiplatform (CCMP wind data for the period 1988–2011. Results show the following. (1 The North Atlantic WPD exhibited a significant increasing trend of 4.45  (W/m2/yr over the past 24 years. (2 The variation in the North Atlantic Ocean WPD shows a noticeable regional difference. More than half of the North Atlantic Ocean has a significantly increasing trend in WPD. The increasing trend in the mid-high latitudes is stronger than that in the low latitudes, and the trend is stronger in the west than in the east. The area with the strongest increasing trend is located along the southern coast of Greenland of 35 (W/m2/yr. (3 There is a noticeable seasonal difference in the variation of WPD. The strongest increasing trend occurs in December-January-February (DJF, followed by September-October-November (SON and March-April-May (MAM, and the weakest occurs in June-July-August (JJA. The increasing trend in different areas is dominated by different seasons. (4 There is no leading or lagging correlation between WPD and the North Atlantic Oscillation (NAO. However, there is a noticeable negative correlation between the Niño3 index and WPD in most of the North Atlantic.

  8. An electrical analogy relating the Atlantic multidecadal oscillation to the Atlantic meridional overturning circulation.

    Directory of Open Access Journals (Sweden)

    Bruce E Kurtz

    Full Text Available The Atlantic meridional overturning circulation (AMOC is the northward flow of surface water to subpolar latitudes where deepwater is formed, balanced by southward abyssal flow and upwelling in the vicinity of the Southern Ocean. It is generally accepted that AMOC flow oscillates with a period of 60-80 years, creating a regular variation in North Atlantic sea surface temperature known as the Atlantic multidecadal oscillation (AMO. This article attempts to answer two questions: how is the AMOC driven and why does it oscillate? Using methods commonly employed by chemical engineers for analyzing processes involving flowing liquids, apparently not previously applied to trying to understand the AMOC, an equation is developed for AMOC flow as a function of the meridional density gradient or the corresponding temperature gradient. The equation is based on the similarity between the AMOC and an industrial thermosyphon loop cooler, which circulates a heat transfer liquid without using a mechanical pump. Extending this equation with an analogy between the flow of heat and electricity explains why the AMOC flow oscillates and what determines its period. Calculated values for AMOC flow and AMO oscillation period are in good agreement with measured values.

  9. Historiske perioder

    DEFF Research Database (Denmark)

    2017-01-01

    For at forstå fortiden og fortællingerne om den, må vi skabe en form for orden og systematik. Her spiller inddelingen af fortiden i historiske perioder en afgørende rolle – og historiske perioder er da også et kompetencemål efter 6. klasse. Videoen diskuterer forskellige principper...... for periodisering. Kronologi og sammenhænge hænger naturligt sammen med historiske perioder. Videoen handler også om forståelser og brug af synkrone og diakrone sammenhænge i faget....

  10. Marine Ecosystem Response to the Atlantic Multidecadal Oscillation

    Science.gov (United States)

    Edwards, Martin; Beaugrand, Gregory; Helaouët, Pierre; Alheit, Jürgen; Coombs, Stephen

    2013-01-01

    Against the backdrop of warming of the Northern Hemisphere it has recently been acknowledged that North Atlantic temperature changes undergo considerable variability over multidecadal periods. The leading component of natural low-frequency temperature variability has been termed the Atlantic Multidecadal Oscillation (AMO). Presently, correlative studies on the biological impact of the AMO on marine ecosystems over the duration of a whole AMO cycle (∼60 years) is largely unknown due to the rarity of continuously sustained biological observations at the same time period. To test whether there is multidecadal cyclic behaviour in biological time-series in the North Atlantic we used one of the world's longest continuously sustained marine biological time-series in oceanic waters, long-term fisheries data and historical records over the last century and beyond. Our findings suggest that the AMO is far from a trivial presence against the backdrop of continued temperature warming in the North Atlantic and accounts for the second most important macro-trend in North Atlantic plankton records; responsible for habitat switching (abrupt ecosystem/regime shifts) over multidecadal scales and influences the fortunes of various fisheries over many centuries. PMID:23460832

  11. Marine ecosystem response to the Atlantic Multidecadal Oscillation.

    Directory of Open Access Journals (Sweden)

    Martin Edwards

    Full Text Available Against the backdrop of warming of the Northern Hemisphere it has recently been acknowledged that North Atlantic temperature changes undergo considerable variability over multidecadal periods. The leading component of natural low-frequency temperature variability has been termed the Atlantic Multidecadal Oscillation (AMO. Presently, correlative studies on the biological impact of the AMO on marine ecosystems over the duration of a whole AMO cycle (∼60 years is largely unknown due to the rarity of continuously sustained biological observations at the same time period. To test whether there is multidecadal cyclic behaviour in biological time-series in the North Atlantic we used one of the world's longest continuously sustained marine biological time-series in oceanic waters, long-term fisheries data and historical records over the last century and beyond. Our findings suggest that the AMO is far from a trivial presence against the backdrop of continued temperature warming in the North Atlantic and accounts for the second most important macro-trend in North Atlantic plankton records; responsible for habitat switching (abrupt ecosystem/regime shifts over multidecadal scales and influences the fortunes of various fisheries over many centuries.

  12. Climate Prediction Center (CPC) Monthly North Atlantic Oscillation (NAO) teleconnection index

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Monthly tabulated index of the North Atlantic Oscillation (NAO) teleconnection pattern. The data spans the period 1950 to present. The index is derived from a...

  13. Climate Prediction Center (CPC) East Atlantic/ Western Russia Teleconnection Pattern Index

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Monthly tabulated index of the East Atlantic/ Western Russia teleconnection pattern. The data spans the period 1950 to present. The index is derived from a rotated...

  14. Decadal slowdown in global air temperature rise triggered by variability in the Atlantic Meridional Overturning Circulation

    Science.gov (United States)

    England, Matthew H.

    2015-04-01

    Various explanations have been proposed for the recent slowdown in global surface air temperature (SAT) rise, either involving enhanced ocean heat uptake or reduced radiation reaching Earth's surface. Among the mechanisms postulated involving enhanced ocean heat uptake, past work has argued for both a Pacific and Atlantic origin, with additional contributions from the Southern Ocean. Here we examine the mechanisms driving 'hiatus' periods originating out of the Atlantic Ocean. We show that while Atlantic-driven hiatuses are entirely plausible and consistent with known climate feedbacks associated with variability in the Atlantic Meridional Overturning Circulation (AMOC), the present climate state is configured to enhance global-average SAT, not reduce it. We show that Atlantic hiatuses are instead characterised by anomalously cool fresh oceanic conditions in the North Atlantic, with the atmosphere advecting the cool temperature signature zonally. Compared to the 1980s and 1990s, however, the mean climate since 2001 has been characterised by a warm saline North Atlantic, suggesting the AMOC cannot be implicated as a direct driver of the current hiatus. We further discuss the impacts of a warm tropical Atlantic on the unprecedented trade wind acceleration in the Pacific Ocean, and propose that this is the main way that the Atlantic has contributed to the present "false pause" in global warming.

  15. Remote impact of North Atlantic sea surface temperature on rainfall in southwestern China during boreal spring

    Science.gov (United States)

    Li, Gang; Chen, Jiepeng; Wang, Xin; Luo, Xia; Yang, Daoyong; Zhou, Wen; Tan, Yanke; Yan, Hongming

    2018-01-01

    As an important oceanic signal, the North Atlantic sea surface temperature (SST) affects not only the climate variability over East China and Northeast China but also can affect climate variability over southwestern China (SWC). Based on station rainfall data and reanalysis datasets, the present study investigates the relationship of North Atlantic SST with SWC rainfall during boreal spring for the period 1979-2016. The results show that there is a significant positive correlation between North Atlantic SST and SWC rainfall during boreal spring. The atmospheric circulation over southern Asia associated with North Atlantic SST is favorable for positive rainfall anomalies. Further analyses show that North Atlantic SST can induce a North Atlantic-western Russia-western Tibetan Plateau-SWC (NRTC) teleconnection wave train from upper level to low level. At low level, two anomalous anticyclones are found over the mid-high latitude of North Atlantic and the western Tibetan Plateau, and two anomalous cyclones are observed over the western Russia and Bay of Bengal (BOB), respectively. The NRTC teleconnection wave train plays a bridging role between the North Atlantic SST and SWC rainfall during boreal spring. Both the observational analysis and two numerical experiments suggest that the North Atlantic SST during boreal spring can induce an anomalous cyclone over BOB by the NRTC teleconnection pattern. The anomalous cyclone over BOB favors moisture transport to SWC, accompanying with significant anomalous ascending motion, and thus results in positive rainfall anomalies in SWC during boreal spring.

  16. The influences of the AMO and NAO on the sedimentary infill in an Azores Archipelago lake since ca. 1350 CE

    Science.gov (United States)

    Hernández, Armand; Sáez, Alberto; Bao, Roberto; Raposeiro, Pedro M.; Trigo, Ricardo M.; Doolittle, Sara; Masqué, Pere; Rull, Valentí; Gonçalves, Vítor; Vázquez-Loureiro, David; Rubio-Inglés, María J.; Sánchez-López, Guiomar; Giralt, Santiago

    2017-07-01

    The location of the Azores Archipelago in the North Atlantic makes this group of islands an excellent setting to study the long-term behavior of large oceanic and atmospheric climate dynamic patterns, such as the Atlantic Multidecadal Oscillation (AMO) and the North Atlantic Oscillation (NAO). Here, we present the impacts of these patterns on Lake Empadadas (Azores Archipelago) from the Medieval Climate Anomaly (MCA) - Little Ice Age (LIA) transition to the present based on sedimentological, geochemical and biological characterizations of the sedimentary record. Multivariate analyses of a number of proxies including X-ray fluorescence (XRF), X-ray diffraction (XRD), total organic and inorganic carbon (TOC and TIC) and diatom life forms abundance reveal that the sedimentary infill evolution has been controlled by (i) fluctuations in the lake level and (ii) variations in organic matter accumulation. Both processes are governed by climate variability and modulated by anthropogenic activities associated with changes on the lake catchment. Changes in these two sedimentary processes have been used to infer five stages: (i) the MCA-LIA transition (ca. 1350-1450 CE) was characterized by a predominantly positive AMO phase, which led to intermediate lake levels and high organic matter concentration; (ii) the first half of the LIA (ca. 1450-1600 CE) was characterized by predominant lowstand conditions and intermediate organic matter deposition mainly related to negative AMO phases; (iii) the second half of the LIA (ca. 1600-1850 CE) was characterized by negative AMO and NAO phases, implying intermediate lake levels and high organic matter deposition; (iv) the Industrial era (ca. 1850-1980 CE) was characterized by the lowest lake level and organic matter accumulation associated with negative AMO phases; and (v) the period spanning between 1980 CE and the present reveals the highest lake levels and low organic matter deposition, being associated with very positive AMO

  17. Mid-Atlantic Regional Wind Energy Institute

    Energy Technology Data Exchange (ETDEWEB)

    Courtney Lane

    2011-12-20

    As the Department of Energy stated in its 20% Wind Energy by 2030 report, there will need to be enhanced outreach efforts on a national, state, regional, and local level to communicate wind development opportunities, benefits and challenges to a diverse set of stakeholders. To help address this need, PennFuture was awarded funding to create the Mid-Atlantic Regional Wind Energy Institute to provide general education and outreach on wind energy development across Maryland, Virginia, Delaware, Pennsylvania and West Virginia. Over the course of the two-year grant period, PennFuture used its expertise on wind energy policy and development in Pennsylvania and expanded it to other states in the Mid-Atlantic region. PennFuture accomplished this through reaching out and establishing connections with policy makers, local environmental groups, health and economic development organizations, and educational institutions and wind energy developers throughout the Mid-Atlantic region. PennFuture conducted two regional wind educational forums that brought together wind industry representatives and public interest organizations from across the region to discuss and address wind development in the Mid-Atlantic region. PennFuture developed the agenda and speakers in collaboration with experts on the ground in each state to help determine the critical issue to wind energy in each location. The sessions focused on topics ranging from the basics of wind development; model ordinance and tax issues; anti-wind arguments and counter points; wildlife issues and coalition building. In addition to in-person events, PennFuture held three webinars on (1) Generating Jobs with Wind Energy; (2) Reviving American Manufacturing with Wind Power; and (3) Wind and Transmission. PennFuture also created a web page for the institute (http://www.midatlanticwind.org) that contains an online database of fact sheets, research reports, sample advocacy letters, top anti-wind claims and information on how to

  18. Arctic warming will promote Atlantic-Pacific fish interchange

    DEFF Research Database (Denmark)

    Wisz, Mary; Broennimann, O.; Grønkjær, Peter

    2015-01-01

    Throughout much of the Quaternary Period, inhospitable environmental conditions above the Arctic Circle have been a formidable barrier separating most marine organisms in the North Atlantic from those in the North Pacific. Rapid warming has begun to lift this barrier, potentially facilitating...... to ecosystems that at present contribute 39% to global marine fish landings...

  19. Amplification of the Atlantic Multidecadal Oscillation associated with the onset of the industrial-era warming

    OpenAIRE

    Moore, G. W. K.; Halfar, J.; Majeed, H.; Adey, W.; Kronz, A.

    2017-01-01

    North Atlantic sea surface temperatures experience variability with a periodicity of 60–80 years that is known as the Atlantic Multidecadal Oscillation (AMO). It has a profound imprint on the global climate system that results in a number of high value societal impacts. However the industrial period, i.e. the middle of the 19th century onwards, contains only two full cycles of the AMO making it difficult to fully characterize this oscillation and its impact on the climate system. ...

  20. Diversidade de Culicidae durante os períodos crepusculares em bioma de Floresta Atlântica e paridade de Anopheles cruzii (Diptera: Culicidae Diversity of Culicidae during the crepuscular periods in Atlantic Forest biome and parity of Anopheles cruzii (Diptera: Culicidae

    Directory of Open Access Journals (Sweden)

    Ana C. D. Bona

    2008-03-01

    dense rain forest in Atlantic Forest, located in the State of the Paraná, named of Palmito State Park. The captures were performed two days in a month, during December 2006 to March 2007, occurring in the matutine and vespertine crepuscular periods. The captures were executed before twilight until after twilight. Twenty five species that belong to Culicidae were identified, the tree most abundant species were Anopheles cruzii (65.2%, Culex sachettae Sirivanakarn & Jacob, 1982 (11.2% e Anopheles bellator Dyar & Knab, 1906 (8.5%. According to variance analysis, significant difference in frequency, was detected between crepuscular periods, for the following species: Aedes scapularis (Rondone, 1848 (p = 0. 03651, Coquillettidia chrysonotum (Peryassu, 1922 (p = 0. 00795, Mansonia fonsecai (Pinto, 1932 (p = 0. 00804, e Runchomyia theobaldi Lane & Cerqueira, 1934 (p = 0. 01996. The tree most captured species didn't show a significant correlation to the climatic factors. The rate parity of Anopheles cruzii was 48%. Didn't have correlation between the abundance with the rate parity. The twilight influences the behavior of Culicidae species. The similarity comparison between matutine and vespertine crepuscular periods revealed an elevated resemblance in the specific composition. A. cruzii was dominant specie in the crepuscular periods. The diversity in the crepuscular periods was considered decrease.

  1. Marine proxy evidence linking decadal North Pacific and Atlantic climate

    Energy Technology Data Exchange (ETDEWEB)

    Hetzinger, S. [University of Toronto Mississauga, CPS-Department, Mississauga, ON (Canada); Leibniz Institute of Marine Sciences, IFM-GEOMAR, Kiel (Germany); Halfar, J. [University of Toronto Mississauga, CPS-Department, Mississauga, ON (Canada); Mecking, J.V.; Keenlyside, N.S. [Leibniz Institute of Marine Sciences, IFM-GEOMAR, Kiel (Germany); University of Bergen, Geophysical Institute and Bjerknes Centre for Climate Research, Bergen (Norway); Kronz, A. [University of Goettingen, Geowissenschaftliches Zentrum, Goettingen (Germany); Steneck, R.S. [University of Maine, Darling Marine Center, Walpole, ME (United States); Adey, W.H. [Smithsonian Institution, Department of Botany, Washington, DC (United States); Lebednik, P.A. [ARCADIS U.S. Inc., Walnut Creek, CA (United States)

    2012-09-15

    Decadal- to multidecadal variability in the extra-tropical North Pacific is evident in 20th century instrumental records and has significant impacts on Northern Hemisphere climate and marine ecosystems. Several studies have discussed a potential linkage between North Pacific and Atlantic climate on various time scales. On decadal time scales no relationship could be confirmed, potentially due to sparse instrumental observations before 1950. Proxy data are limited and no multi-centennial high-resolution marine geochemical proxy records are available from the subarctic North Pacific. Here we present an annually-resolved record (1818-1967) of Mg/Ca variations from a North Pacific/Bering Sea coralline alga that extends our knowledge in this region beyond available data. It shows for the first time a statistically significant link between decadal fluctuations in sea-level pressure in the North Pacific and North Atlantic. The record is a lagged proxy for decadal-scale variations of the Aleutian Low. It is significantly related to regional sea surface temperature and the North Atlantic Oscillation (NAO) index in late boreal winter on these time scales. Our data show that on decadal time scales a weaker Aleutian Low precedes a negative NAO by several years. This atmospheric link can explain the coherence of decadal North Pacific and Atlantic Multidecadal Variability, as suggested by earlier studies using climate models and limited instrumental data. (orig.)

  2. Timing and magnitude of equatorial Atlantic surface warming during the last glacial bipolar oscillation

    Directory of Open Access Journals (Sweden)

    S. Weldeab

    2012-10-01

    Full Text Available The timing and magnitude of millennial-scale thermal oscillation in the equatorial Atlantic during the last glacial and marine isotope stage 3 have been perceived as merely a response to meltwater-induced perturbations of the northern high latitude climate. The relatively asymmetric distribution of available temperature records has so far impeded testing whether this view is valid across the equatorial Atlantic. This study presents a centennially resolved record of Mg/Ca-derived sea surface temperature (SST estimates from the eastern equatorial Atlantic (EEA and a core top-based proxy validation. Multivariate analysis of the EEA core top data indicates that the Mg/Ca ratio varies by 8 ± 2% per unit SST (°C and 1 ± 0.9% per unit salinity (psu change, indicating that temperature is the most dominant factor controlling planktonic foraminiferal Mg/Ca variation. The EEA SST time series exhibits a close correlation between episodes of rapid equatorial surface water warming, the onset of massive meltwater inputs into the North Atlantic (Heinrich events H3–H6, and Antarctic climate changes, indicating that the EEA was very sensitive to millennial-scale bipolar oscillations. Rapid EEA SST rise between 0.8 °C and 2 °C, synchronous with the onset of Heinrich events, is consistent with the concept of tropical Atlantic warming in response to meltwater-induced perturbation of Atlantic meridional ocean circulation (AMOC. At variance with model results that suggest a basin-wide SST rise during and rapid surface cooling concomitant with the termination of Heinrich events, this study indicates persistently elevated EEA SST during and up to 2300 yr after the abrupt termination of Heinrich events. This study emphasizes that changes in wind-induced low-latitude zonal surface currents were crucial in shaping the spatial heterogeneity and duration of equatorial Atlantic surface water warmth.

  3. Forest productivity in southwestern Europe is controlled by coupled North Atlantic and Atlantic Multidecadal Oscillations.

    Science.gov (United States)

    Madrigal-González, Jaime; Ballesteros-Cánovas, Juan A; Herrero, Asier; Ruiz-Benito, Paloma; Stoffel, Markus; Lucas-Borja, Manuel E; Andivia, Enrique; Sancho-García, Cesar; Zavala, Miguel A

    2017-12-20

    The North Atlantic Oscillation (NAO) depicts annual and decadal oscillatory modes of variability responsible for dry spells over the European continent. The NAO therefore holds a great potential to evaluate the role, as carbon sinks, of water-limited forests under climate change. However, uncertainties related to inconsistent responses of long-term forest productivity to NAO have so far hampered firm conclusions on its impacts. We hypothesize that, in part, such inconsistencies might have their origin in periodical sea surface temperature anomalies in the Atlantic Ocean (i.e., Atlantic Multidecadal Oscillation, AMO). Here we show strong empirical evidence in support of this hypothesis using 120 years of periodical inventory data from Iberian pine forests. Our results point to AMO+ NAO+ and AMO-NAO- phases as being critical for forest productivity, likely due to decreased winter water balance and abnormally low winter temperatures, respectively. Our findings could be essential for the evaluation of ecosystem functioning vulnerabilities associated with increased climatic anomalies under unprecedented warming conditions in the Mediterranean.

  4. INTRACELLULAR Ca2+ HOMEOSTASIS

    Directory of Open Access Journals (Sweden)

    Shahdevi Nandar Kurniawan

    2015-01-01

    Full Text Available Ca2+ signaling functions to regulate many cellular processes. Dynamics of Ca2+ signaling or homeostasis is regulated by the interaction between ON and OFF reactions that control Ca2+ flux in both the plasma membrane and internal organelles such as the endoplasmic reticulum (ER and mitochondria. External stimuli activate the ON reactions, which include Ca2+ into the cytoplasm either through channels in the plasma membrane or from internal storage like in ER. Most of the cells utilize both channels/sources, butthere area few cells using an external or internal source to control certain processes. Most of the Ca2+ entering the cytoplasm adsorbed to the buffer, while a smaller part activate effect or to stimulate cellular processes. Reaction OFF is pumping of cytoplasmic Ca2+ using a combination mechanism of mitochondrial and others. Changes in Ca2+ signal has been detected in various tissues isolated from animals induced into diabetes as well as patients with diabetes. Ca2+ signal interference is also found in sensory neurons of experimental animals with diabetes. Ca2+ signaling is one of the main signaling systems in the cell.

  5. North Atlantic Oscillation (NAO and insect damage in Serbian forests

    Directory of Open Access Journals (Sweden)

    Ducić V.

    2012-01-01

    Full Text Available This paper examines the relationship between North Atlantic Oscillation (NAO and damage made by insects in Serbian forests. The damage has been separated into three groups: bark beetles, gypsy moth and damage made by other insects. For North Atlantic Oscillation the NAO index is used. The period of investigation was 1969-2001. Data were studied on an annual scale as well as with five-year moving averages. Analysis showed a statistically significant correlation for NAO index and gypsy moth.

  6. PERIODIC BEHAVIORS

    NARCIS (Netherlands)

    Napp, Diego; Put, Marius van der; Shankar, Shiva

    2010-01-01

    This paper studies behaviors that are defined on a torus, or equivalently, behaviors defined in spaces of periodic functions, and establishes their basic properties analogous to classical results of Malgrange, Palamodov, Oberst et al. for behaviors on R(n). These properties-in particular the

  7. 77 FR 69596 - Atlantic Highly Migratory Species; Advisory Panel for Atlantic Highly Migratory Species Southeast...

    Science.gov (United States)

    2012-11-20

    ... National Oceanic and Atmospheric Administration RIN 0648-XC321 Atlantic Highly Migratory Species; Advisory Panel for Atlantic Highly Migratory Species Southeast Data, Assessment, and Review Workshops AGENCY... (AP) for Atlantic Highly Migratory Species (HMS) Southeast Data, Assessment, and Review (SEDAR...

  8. Atmospheric circulation in northern hemisphere and north atlantic oscillation

    Directory of Open Access Journals (Sweden)

    Александр Вадимович Холопцев

    2015-08-01

    Full Text Available Conditions under which statistical connections of interannual changes of repitition duration periods in Northern hemisphere of elementary circulation mechanisms associated to meridional northern and meridional southern groups with variations of North Atlantic oscillation are significant were revealed. It is shown, that the characteristics changes of these connections taking place in modern period can be caused by distribution changes of distribution of sea surface temperatures

  9. Mid-Pliocene Atlantic Meridional Overturning Circulation Not Unlike Modern

    Science.gov (United States)

    Zhang, Z.-S.; Nisancioglu, K. H.; Chandler, M. A.; Haywood, A. M.; Otto-Bliesner, B. L.; Ramstein, G.; Stepanek, C.; Abe-Ouchi, A.; Chan, W. -L.; Sohl, L. E.

    2013-01-01

    In the Pliocene Model Intercomparison Project (PlioMIP), eight state-of-the-art coupled climate models have simulated the mid-Pliocene warm period (mPWP, 3.264 to 3.025 Ma). Here, we compare the Atlantic Meridional Overturning Circulation (AMOC), northward ocean heat transport and ocean stratification simulated with these models. None of the models participating in PlioMIP simulates a strong mid-Pliocene AMOC as suggested by earlier proxy studies. Rather, there is no consistent increase in AMOC maximum among the PlioMIP models. The only consistent change in AMOC is a shoaling of the overturning cell in the Atlantic, and a reduced influence of North Atlantic Deep Water (NADW) at depth in the basin. Furthermore, the simulated mid-Pliocene Atlantic northward heat transport is similar to the pre-industrial. These simulations demonstrate that the reconstructed high-latitude mid-Pliocene warming can not be explained as a direct response to an intensification of AMOC and concomitant increase in northward ocean heat transport by the Atlantic.

  10. Atlantic Flyway Breeding Waterfowl Survey

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Atlantic Flyway Technical Section initiated this breeding waterfowl survey in 11 northeast states ranging from New Hampshire to Virginia.

  11. Virginia Atlantic Coast Recreational Use

    Data.gov (United States)

    Virginia Department of Environmental Quality — As a member of the Mid-Atlantic Regional Council on the Ocean (MARCO), Virginia, through its Coastal Zone Management (CZM) Program, collected information on how the...

  12. Atlantic Offshore Seabird Dataset Catalog

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Several bureaus within the Department of Interior compiled available information from seabird observation datasets from the Atlantic Outer Continental Shelf into a...

  13. VA Atlantic Coast Recreational Use

    Data.gov (United States)

    Virginia Department of Environmental Quality — As a member of the Mid-Atlantic Regional Council on the Ocean (MARCO), Virginia, through its Coastal Zone Management (CZM) Program, collected information on how the...

  14. Atlantic Flyway Sea Duck Survey

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Atlantic Flyway Sea Duck Survey, conducted from 1991 to 2002 by the U.S. Fish and Wildlife Service, was established to record sea duck numbers using near shore...

  15. North Atlantic warming: patterns of long-term trend and multidecadal variability

    Energy Technology Data Exchange (ETDEWEB)

    Polyakov, Igor V.; Alexeev, Vladimir A.; Zhang, Xiangdong [University of Alaska Fairbanks, International Arctic Research Center, Fairbanks, AK (United States); Bhatt, Uma S. [University of Alaska Fairbanks, Geophysical Institute, Fairbanks, AK (United States); Polyakova, Evgenia I. [Stanford University, Department of Geological and Environmental Studies, Stanford, CA (United States)

    2010-02-15

    Climate fluctuations in the North Atlantic Ocean have wide-spread implications for Europe, Africa, and the Americas. This study assesses the relative contribution of the long-term trend and variability of North Atlantic warming using EOF analysis of deep-ocean and near-surface observations. Our analysis demonstrates that the recent warming over the North Atlantic is linked to both long-term (including anthropogenic and natural) climate change and multidecadal variability (MDV, {proportional_to}50-80 years). Our results suggest a general warming trend of 0.031 {+-} 0.006 C/decade in the upper 2,000 m North Atlantic over the last 80 years of the twentieth century, although during this time there are periods in which short-term trends were strongly amplified by MDV. For example, MDV accounts for {proportional_to}60% of North Atlantic warming since 1970. The single-sign basin-scale pattern of MDV with prolonged periods of warming (cooling) in the upper ocean layer and opposite tendency in the lower layer is evident from observations. This pattern is associated with a slowdown (enhancement) of the North Atlantic thermohaline overturning circulation during negative (positive) MDV phases. In contrast, the long-term trend exhibits warming in tropical and mid-latitude North Atlantic and a pattern of cooling in regions associated with major northward heat transports, consistent with a slowdown of the North Atlantic circulation as evident from observations and confirmed by selected modeling results. This localized cooling has been masked in recent decades by warming during the positive phase of MDV. Finally, since the North Atlantic Ocean plays a crucial role in establishing and regulating the global thermohaline circulation, the multidecadal fluctuations discussed here should be considered when assessing long-term climate change and variability, both in the North Atlantic and at global scales. (orig.)

  16. 78 FR 58249 - Fisheries of the Caribbean, Gulf of Mexico, and South Atlantic; Snapper-Grouper Fishery Off the...

    Science.gov (United States)

    2013-09-23

    ..., Gulf of Mexico, and South Atlantic; Snapper-Grouper Fishery Off the Southern Atlantic States... between black sea bass pot gear and whales listed under the Endangered Species Act (ESA) during periods of large whale migrations and during the northern right whale calving season off of the southeastern coast...

  17. 78 FR 39700 - Fisheries of the Caribbean, Gulf of Mexico, and South Atlantic; Snapper-Grouper Fishery off the...

    Science.gov (United States)

    2013-07-02

    ..., Gulf of Mexico, and South Atlantic; Snapper-Grouper Fishery off the Southern Atlantic States... prevent interactions between black sea bass pot gear and whales listed under the Endangered Species Act (ESA) during periods of large whale migrations and during the northern right whale calving season off...

  18. Desulfurizing Ability of the CaOsatd.-CaCl2-CaF2 Slags

    Science.gov (United States)

    Liu, Jiazhan; Kobayashi, Yoshinao

    2017-04-01

    Desulfurizing ability of the CaO-CaCl2-CaF2 slags saturated with CaO has been investigated from the viewpoint of the sulfide capacity and CaO solubility. The CaO-CaCl2-CaF2 slags containing small amounts of Cu2O and CaS were inserted in a CaO crucible with metallic copper. The CaO crucible was sealed in a nickel holder to prevent the evaporation of CaCl2, then heated up and kept at temperatures from 1573 K (1300 °C) to 1673 K (1400 °C) for 24 hours, which enabled the system inside the CaO crucible to reach the equilibrium. As expected, the sulfide capacity derived from the data obtained as well as CaO solubility of the slag increase with an increase in temperature at a constant ratio of CaCl2/CaF2. The solubility of CaO increases by the replacement of CaF2 with CaCl2, whereas the sulfide capacity slightly decreases and the activity coefficient of CaS ( γ CaS) increases. This suggests that CaF2 has stronger interaction with CaS than CaCl2. The sulfur distribution ratio between carbon-saturated iron melts and the CaO-CaCl2 slag has been calculated to be about 10 000 at 1573 K (1300 °C) using the sulfide capacity obtained, which value is still large enough even with the replacement of CaF2 by CaCl2.

  19. Anesthesia induces stress in Atlantic salmon (Salmo salar), Atlantic cod (Gadus morhua) and Atlantic halibut (Hippoglossus hippoglossus).

    Science.gov (United States)

    Zahl, Inger Hilde; Kiessling, Anders; Samuelsen, Ole Bent; Olsen, Rolf Erik

    2010-09-01

    Stress in response to anesthesia with benzocaine, MS-222, metomidate and isoeugenol was studied in Atlantic salmon (Salmo salar), Atlantic halibut (Hippoglossus hippoglossus), and Atlantic cod (Gadus morhua) with no concomitant stress from handling or confinement in association with anesthesia or sampling. All of the anesthetics tested induced a stress response in all species, displayed by a release of cortisol to the water. MS-222 anesthesia elicited the highest cortisol release rates, reaching maximum levels 0.5 h post-exposure and returning to basal levels after 3-4 h. Benzocaine anesthesia caused a bimodal response where the initial peak in cortisol release rate was followed by a second increase lasting towards the end of the trial (6 h). This bimodality was more profound in Atlantic salmon than in Atlantic halibut and Atlantic cod. Metomidate anesthesia induced the lowest release of cortisol of the agents tested in both Atlantic halibut and Atlantic cod, but resulted in a bimodal response in Atlantic salmon where the initial increase in cortisol release was followed by a larger increase peaking at 2-2.5 h post exposure before returning to basal levels after 5 h. The stress induced in Atlantic salmon by isoeugenol anesthesia resembled that of MS-222, but did not reach the same elevated level. Overall, the cortisol release was most profound in Atlantic salmon followed by Atlantic halibut and Atlantic cod.

  20. Teale CA. Counties

    Data.gov (United States)

    California Department of Resources — California Spatial Information System (CaSIL) is a project designed to improve access to geo-spatial and geo-spatial related data information throughout the state of...

  1. Carbon storage in the mid-depth Atlantic during millennial-scale climate events

    Science.gov (United States)

    Lacerra, Matthew; Lund, David; Yu, Jimin; Schmittner, Andreas

    2017-08-01

    Carbon isotope minima were a ubiquitous feature of the mid-depth Atlantic during Heinrich Stadial 1 (HS1, 14.5-17.5 kyr BP) and the Younger Dryas (YD, 11.5-12.9 kyr BP), yet their cause remains unclear. Recent evidence indicates that North Atlantic processes triggered the δ13C anomalies, with weakening of the Atlantic Meridional Overturning Circulation (AMOC) being the most likely driver. Model simulations suggest that slowing of the AMOC increases the residence time of mid-depth waters in the Atlantic, resulting in the accumulation of respired carbon. Here we assess ΣCO2 variability in the South Atlantic using benthic foraminiferal B/Ca, a proxy for [CO32-]. Using replicated high-resolution B/Ca records from 2 km water depth on the Brazil Margin, we show that [CO32-] decreased during HS1 and the YD, synchronous with apparent weakening of the AMOC. The [CO32-] response is smaller than in the tropical North Atlantic during HS1, indicating there was a north-south gradient in the [CO32-] signal similar to that for δ13C. The implied variability in ΣCO2 is consistent with model results, suggesting that carbon is temporarily sequestered in the mid-depth Atlantic during millennial-scale stadial events. Using a carbon isotope mass balance, we estimate that approximately 75% of the HS1 δ13C signal at the Brazil Margin was driven by accumulation of remineralized carbon, highlighting the nonconservative behavior of δ13C during the last deglaciation.

  2. Carotenoid dynamics in Atlantic salmon

    Directory of Open Access Journals (Sweden)

    Omholt Stig W

    2006-04-01

    Full Text Available Abstract Background Carotenoids are pigment molecules produced mainly in plants and heavily exploited by a wide range of organisms higher up in the food-chain. The fundamental processes regulating how carotenoids are absorbed and metabolized in vertebrates are still not fully understood. We try to further this understanding here by presenting a dynamic ODE (ordinary differential equation model to describe and analyse the uptake, deposition, and utilization of a carotenoid at the whole-organism level. The model focuses on the pigment astaxanthin in Atlantic salmon because of the commercial importance of understanding carotenoid dynamics in this species, and because deposition of carotenoids in the flesh is likely to play an important life history role in anadromous salmonids. Results The model is capable of mimicking feed experiments analyzing astaxanthin uptake and retention over short and long time periods (hours, days and years under various conditions. A sensitivity analysis of the model provides information on where to look for possible genetic determinants underlying the observed phenotypic variation in muscle carotenoid retention. Finally, the model framework is used to predict that a specific regulatory system controlling the release of astaxanthin from the muscle is not likely to exist, and that the release of the pigment into the blood is instead caused by the androgen-initiated autolytic degradation of the muscle in the sexually mature salmon. Conclusion The results show that a dynamic model describing a complex trait can be instrumental in the early stages of a project trying to uncover underlying determinants. The model provides a heuristic basis for an experimental research programme, as well as defining a scaffold for modelling carotenoid dynamics in mammalian systems.

  3. Carotenoid dynamics in Atlantic salmon.

    Science.gov (United States)

    Rajasingh, Hannah; Øyehaug, Leiv; Våge, Dag Inge; Omholt, Stig W

    2006-04-18

    Carotenoids are pigment molecules produced mainly in plants and heavily exploited by a wide range of organisms higher up in the food-chain. The fundamental processes regulating how carotenoids are absorbed and metabolized in vertebrates are still not fully understood. We try to further this understanding here by presenting a dynamic ODE (ordinary differential equation) model to describe and analyse the uptake, deposition, and utilization of a carotenoid at the whole-organism level. The model focuses on the pigment astaxanthin in Atlantic salmon because of the commercial importance of understanding carotenoid dynamics in this species, and because deposition of carotenoids in the flesh is likely to play an important life history role in anadromous salmonids. The model is capable of mimicking feed experiments analyzing astaxanthin uptake and retention over short and long time periods (hours, days and years) under various conditions. A sensitivity analysis of the model provides information on where to look for possible genetic determinants underlying the observed phenotypic variation in muscle carotenoid retention. Finally, the model framework is used to predict that a specific regulatory system controlling the release of astaxanthin from the muscle is not likely to exist, and that the release of the pigment into the blood is instead caused by the androgen-initiated autolytic degradation of the muscle in the sexually mature salmon. The results show that a dynamic model describing a complex trait can be instrumental in the early stages of a project trying to uncover underlying determinants. The model provides a heuristic basis for an experimental research programme, as well as defining a scaffold for modelling carotenoid dynamics in mammalian systems.

  4. Links between salinity variation in the Caribbean and North Atlantic thermohaline circulation.

    Science.gov (United States)

    Schmidt, Matthew W; Spero, Howard J; Lea, David W

    2004-03-11

    Variations in the strength of the North Atlantic Ocean thermohaline circulation have been linked to rapid climate changes during the last glacial cycle through oscillations in North Atlantic Deep Water formation and northward oceanic heat flux. The strength of the thermohaline circulation depends on the supply of warm, salty water to the North Atlantic, which, after losing heat to the atmosphere, produces the dense water masses that sink to great depths and circulate back south. Here we analyse two Caribbean Sea sediment cores, combining Mg/Ca palaeothermometry with measurements of oxygen isotopes in foraminiferal calcite in order to reconstruct tropical Atlantic surface salinity during the last glacial cycle. We find that Caribbean salinity oscillated between saltier conditions during the cold oxygen isotope stages 2, 4 and 6, and lower salinities during the warm stages 3 and 5, covarying with the strength of North Atlantic Deep Water formation. At the initiation of the Bølling/Allerød warm interval, Caribbean surface salinity decreased abruptly, suggesting that the advection of salty tropical waters into the North Atlantic amplified thermohaline circulation and contributed to high-latitude warming.

  5. 76 FR 72383 - Atlantic Highly Migratory Species; Atlantic Shark Management Measures

    Science.gov (United States)

    2011-11-23

    ... Administration 50 CFR Part 635 RIN 0648-BA17 Atlantic Highly Migratory Species; Atlantic Shark Management...) and fishery management plan (FMP) amendment that would consider catch shares for the Atlantic shark... design elements for potential catch shares programs in the Atlantic shark fisheries. Additionally, NMFS...

  6. The Effects of Temperature and Salinity on Mg Incorporation in Planktonic Foraminifera Globigerinoides ruber (white): Results from a Global Sediment Trap Mg/Ca Database

    Science.gov (United States)

    Gray, W. R.; Weldeab, S.; Lea, D. W.

    2015-12-01

    Mg/Ca in Globigerinoides ruber is arguably the most important proxy for sea surface temperature (SST) in tropical and sub tropical regions, and as such guides our understanding of past climatic change in these regions. However, the sensitivity of Mg/Ca to salinity is debated; while analysis of foraminifera grown in cultures generally indicates a sensitivity of 3 - 6% per salinity unit, core-top studies have suggested a much higher sensitivity of between 15 - 27% per salinity unit, bringing the utility of Mg/Ca as a SST proxy into dispute. Sediment traps circumvent the issues of dissolution and post-depositional calcite precipitation that hamper core-top calibration studies, whilst allowing the analysis of foraminifera that have calcified under natural conditions within a well constrained period of time. We collated previously published sediment trap/plankton tow G. ruber (white) Mg/Ca data, and generated new Mg/Ca data from a sediment trap located in the highly-saline tropical North Atlantic, close to West Africa. Calcification temperature and salinity were calculated for the time interval represented by each trap/tow sample using World Ocean Atlas 2013 data. The resulting dataset comprises >240 Mg/Ca measurements (in the size fraction 150 - 350 µm), that span a temperature range of 18 - 28 °C and 33.6 - 36.7 PSU. Multiple regression of the dataset reveals a temperature sensitivity of 7 ± 0.4% per °C (p < 2.2*10-16) and a salinity sensitivity of 4 ± 1% per salinity unit (p = 2*10-5). Application of this calibration has significant implications for both the magnitude and timing of glacial-interglacial temperature changes when variations in salinity are accounted for.

  7. Atlantic menhaden processing plant test tagging data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Atlantic menhaden are a schooling forage fish species, which are subject to a large commercial purse seine fishery. Atlantic menhaden are harvested for reduction...

  8. Atlantic NAD 83 OCS Planning Areas

    Data.gov (United States)

    Bureau of Ocean Energy Management, Department of the Interior — This data set contains BOEM Planning Area outlines in ESRI shapefile format for the BOEM Atlantic Region. The old Atlantic Planning Area outlines were changed as of...

  9. Investigation of the MBL Cloud Macro- and Micro-physical Properties over Pacific and Atlantic Oceans

    Science.gov (United States)

    Xi, B.; Dong, X.

    2013-12-01

    Marine boundary layer (MBL) cloud is an important cloud type in global climate system, and its macro- and micro- physical properties relate with not only the radiation budgets but also affect the sea surface temperature. Two DOE ARM Mobile Facilities (AMF1 and AMF2) were recently deployed at both Atlantic and Pacific Oceans. One was at the Graciosa Island, Azores in context of the Clouds, Aerosol and Precipitation in the Marine Boundary Layer (CAP-MBL) field campaign and the AMF1 collected the most continuous, valuable and comprehensive data of MBL clouds from Jun. 2009 to Dec. 2010. The other filed campaign is the Marine ARM GPCI Investigation of Clouds (MAGIC) IOP, which will provide a great opportunity for us to do the analysis of MBL over Pacific Ocean. The ARM Mobile Facility (AMF2) has been deployed on the Horizon Line cargo ship Spirit traversing the route between Los Angeles, CA and Honolulu, HI for one full year (Oct. 2012 to Sept. 2013) with two additional 2-week intensive observational periods in January and July 2013, such as including additional instruments and more soundings (3-hr). The AMF2 has very similar data sets as the AMF1 over Azores but will not focus on one single point. The AMF2 observations, as well as retrievals for MBL clouds during MAGIC will allow us to compare the MBL cloud properties between North Atlantic and Pacific Oceans. In this study, we will compare the MBL clouds macro- and micro- physical properties over two Oceans. These macro- and micro- physical properties of MBL clouds are derived from AMF1 and AMF2 measurements. In details, the cloud heights are derived from radar/lidar pairs; the cloud temperatures are from linearly interpreted soundings; liquid water path (LWP) is retrieved from microwave radiometer; cloud condensation nuclei are derived from AOS measurements under super-saturation ratio at 0.2. The MBL cloud microphysical properties at daytime ( cloud effective radius, optical thickness, and number concentration

  10. Turbidity, SOLAR RADIATION - ATMOSPHERIC and other data from NOAA Ship WHITING in the NW Atlantic and North Atlantic Ocean from 1994-08-03 to 1994-09-29 (NODC Accession 9400204)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Conductivity, Temperature and Depth (CTD) and other data were collected in NW Atlantic (limit-40 W) from NOAA Ship WHITING. The data was collected over a period...

  11. Atlantic Seaduck Project

    Science.gov (United States)

    Perry, M.C.; Hanson, Alan; Kerekes, Joseph; Paquet, Julie

    2006-01-01

    Atlantic Seaduck Project is being conducted to learn more about the breeding and moulting areas of seaducks in northern Canada and more about their feeding ecology on wintering areas, especially Chesapeake Bay. Satellite telemetry is being used to track surf scoters wintering in Chesapeake Bay, Maryland and black scoters on migrational staging areas in New Brunswick, Canada to breeding and moulting areas in northern Canada. Various techniques used to capture the scoters included mist netting, night-lighting, and net capture guns. All captured ducks were transported to a veterinary hospital where surgery was conducted following general anaesthesia procedures. A PTT100 transmitter (39 g) manufactured by Microwave, Inc., Columbia, Maryland was implanted into the duck?s abdominal cavity with an external (percutaneous) antenna. Eight of the surf scoters from Chesapeake Bay successfully migrated to possible breeding areas in Canada and all 13 of the black scoters migrated to suspected breeding areas. Ten of the 11 black scoter males migrated to James Bay presumably for moulting. Updated information from the ARGOS Systems aboard the NOAA satellites on scoter movements was made accessible on the Patuxent Website. Habitat cover types of locations using GIS (Geographical Information Systems) and aerial photographs (in conjunction with remote sensing software) are currently being analyzed to build thematic maps with varying cosmetic layer applications. Many factors related to human population increases have been implicated in causing changes in the distribution and abundance of wintering seaducks. Analyses of the gullet (oesophagus and proventriculus) and the gizzard of seaducks are currently being conducted to determine if changes from historical data have occurred. Scoters in the Bay feed predominantly on the hooked mussel and several species of clams. The long-tailed duck appears to select the gem clam in greater amounts than other seaducks, but exhibits a diverse diet of

  12. Variation in the diel vertical distributions of larvae and transforming stages of oceanic fishes across the tropical and equatorial Atlantic

    Science.gov (United States)

    Olivar, M. Pilar; Contreras, Tabit; Hulley, P. Alexander; Emelianov, Mikhail; López-Pérez, Cristina; Tuset, Víctor; Castellón, Arturo

    2018-01-01

    The vertical distributions of early developmental stages of oceanic fishes were investigated across the tropical and equatorial Atlantic, from oligotrophic waters close to the Brazilian coast to more productive waters close to the Mauritanian Upwelling Region. Stratification of the water column was observed throughout the study region. Fishes were caught with a MOCNESS-1 net with mouth area of 1 m2 at 11 stations. Each station was sampled both during the day and at night within a single 24-h period. The investigation covered both larvae and transforming stages from the surface to 800 m depth. Distribution patterns were analysed, and weighted mean depths for the larvae and transforming stages of each species were calculated for day and night conditions. Forty-seven different species were found. The highest number of species occurred in the three stations south of Cape Verde Islands, characterized by a mixture of South Atlantic Central Water (SACW) and Eastern North Atlantic Central Water (ENACW). There was a marked drop in species richness in the three stations closer to the African upwelling, dominated by ENACW. The highest abundances occurred in the families Myctophidae, Sternoptychidae, Gonostomatidae and Phosichthyidae. Day and night vertical distributions of larvae and transforming stages showed contrasting patterns, both in the depths of the main concentration layers in the water column, and in the diel migration patterns (where these were observed). Larvae generally showed a preference for the upper mixed layer (ca. 0-50 m) and upper thermocline (ca. 50-100 m), except for sternoptychids, which were also abundant in the lower thermocline layer (100-200 m) and even extended into the mesopelagic zone (down to 500 m). Transforming stages showed a more widespread distribution, with main concentrations in the mesopelagic zone (200-800 m). Larvae showed peak concentrations in the more illuminated and zooplankton-rich upper mixed layers during the day and a wider

  13. Atlantic CFC data in CARINA

    Directory of Open Access Journals (Sweden)

    R. Steinfeldt

    2010-01-01

    Full Text Available Water column data of carbon and carbon-relevant parameters have been collected and merged into a new database called CARINA (CARbon IN the Atlantic. In order to provide a consistent data set, all data have been examined for systematic biases and adjusted if necessary (secondary quality control (QC. The CARINA data set is divided into three regions: the Arctic/Nordic Seas, the Atlantic region and the Southern Ocean. Here we present the CFC data for the Atlantic region, including the chlorofluorocarbons CFC-11, CFC-12 and CFC-113 as well as carbon tetrachloride (CCl4. The methods applied for the secondary quality control, a crossover analyses, the investigation of CFC ratios in the ocean and the CFC surface saturation are presented. Based on the results, the CFC data of some cruises are adjusted by a certain factor or given a "poor'' quality flag.

  14. Variability in north tropical atlantic over the last 20 000 years and holocene gulf stream activity; Variabilite au cours des derniers 20 000 ans de l'hydrologie de l'atlantique tropical nord et de l'activite du gulf stream a partir de la composition isotopique de l'oxygene et de la composition en elements trace des foraminferes planctoniques profonds

    Energy Technology Data Exchange (ETDEWEB)

    Cleroux, C

    2007-10-15

    Modern oceanographical studies shown that most of the ocean heat content in the North Atlantic Western Boundary Current region is stored in the upper 400 meters. To study past heat content and Gulf Stream activity, we performed coupled analyses of oxygen isotopic and trace elemental composition on several foraminifera species to reconstruct upper water column temperature and salinity. Calcification depths of Globorotalia inflata, Globorotalia truncatulinoides and Pulleniatina obliquiloculata have been constrain by correlating modern hydrographic data to oxygen isotopic measurement of North Atlantic core-top samples. We found that the three deep-dwelling foraminifera species have a preferred habitat at the base of the seasonal thermocline (Cleroux et al, 2007). The same set of North Atlantic core-tops has been used to define relationships between trace elemental compositions and temperature. We established calibrations between Mg/Ca ratio or Sr/Ca ratio and temperature for the three deep-dwelling foraminifera (Cleroux et al, submitted). We apply this strategy on the core MD99-2203 located off Cape Hatteras where the Gulf Stream separate from the United States coast. High-resolution surface reconstructions over the Holocene show low amplitude periodic temperature and salinity changes that could be related to NAO type mechanisms. Large hydrological changes in sub-surface reflect variations of Labrador current and Mode Water influences. Using recent studies on Mode Water formation and Gulf Stream heat advection, we interpret our results in term of ocean heat content and Gulf Stream activity. (author)

  15. Biomarker CA125

    DEFF Research Database (Denmark)

    Kargo, Anette Stolberg

    Background: The majority of patients with ovarian cancer (OC) are diagnosed with advanced disease (70-80 %) and will experience disease relapse with only limited curative potential. Early initiation of relapse treatment based on rising CA125 alone does not improve survival. Increasing CA125 can...... be detected months before symptoms arise and recurrence is visible on imaging. Therefore, biochemical detection of potential relapse by CA125 assessment can cause significant distress. A decision aid (DA) is a tool that provides information and describes advantages and disadvantages of a specific intervention...... patient organisations and cancer societies. First, a focus group of seven former OC patients was performed followed by a quantitative rating of the DA pilot version. The DA was adapted accordingly and then tested in 14 OC patients with recurrence using a structured interview guide (alpha testing). A final...

  16. Crosstalk between mitochondrial and sarcoplasmic reticulum Ca2+ cycling modulates cardiac pacemaker cell automaticity.

    Directory of Open Access Journals (Sweden)

    Yael Yaniv

    Full Text Available Mitochondria dynamically buffer cytosolic Ca(2+ in cardiac ventricular cells and this affects the Ca(2+ load of the sarcoplasmic reticulum (SR. In sinoatrial-node cells (SANC the SR generates periodic local, subsarcolemmal Ca(2+ releases (LCRs that depend upon the SR load and are involved in SANC automaticity: LCRs activate an inward Na(+-Ca(2+ exchange current to accelerate the diastolic depolarization, prompting the ensemble of surface membrane ion channels to generate the next action potential (AP.To determine if mitochondrial Ca(2+ (Ca(2+ (m, cytosolic Ca(2+ (Ca(2+ (c-SR-Ca(2+ crosstalk occurs in single rabbit SANC, and how this may relate to SANC normal automaticity.Inhibition of mitochondrial Ca(2+ influx into (Ru360 or Ca(2+ efflux from (CGP-37157 decreased [Ca(2+](m to 80 ± 8% control or increased [Ca(2+](m to 119 ± 7% control, respectively. Concurrent with inhibition of mitochondrial Ca(2+ influx or efflux, the SR Ca(2+ load, and LCR size, duration, amplitude and period (imaged via confocal linescan significantly increased or decreased, respectively. Changes in total ensemble LCR Ca(2+ signal were highly correlated with the change in the SR Ca(2+ load (r(2 = 0.97. Changes in the spontaneous AP cycle length (Ru360, 111 ± 1% control; CGP-37157, 89 ± 2% control in response to changes in [Ca(2+](m were predicted by concurrent changes in LCR period (r(2 = 0.84.A change in SANC Ca(2+ (m flux translates into a change in the AP firing rate by effecting changes in Ca(2+ (c and SR Ca(2+ loading, which affects the characteristics of spontaneous SR Ca(2+ release.

  17. Variations in water level for Lake Turkana in the past 8500 years near Mt. Porr, Kenya and the transition from the African Humid Period to Holocene aridity

    Science.gov (United States)

    Forman, Steven L.; Wright, David K.; Bloszies, Christopher

    2014-08-01

    A stratigraphic and geomorphic study of relict beaches up to 80 m above current water level of Lake Turkana reveal four major lake level fluctuations of >50 m between ca 8.5 and 4.5 ka during the transition from the African Humid Period to Holocene aridity. We hypothesize that high stands of Lake Turkana reflect complex hydrological processes with variability in Atlantic and Indian Ocean-derived moisture into East Africa, ultimately linked to changes in sea surface temperatures (SSTs). Lake level rise was also amplified regionally by increased precipitation causing overflow from the adjacent Suguta and Chew Bahir basins, particularly during high stands at ca >8.5 ka and at 6.4 ka. The timing of transgressive and regressive events is constrained by 14C dating of carefully selected lacustrine mollusks, incorporation of previous shell ages with sufficient elevational control, and OSL dating of quartz grains from littoral and sublittoral deposits by a multiple aliquot regeneration (MAR) approach. There was a high water level up to at least 70 m at >8.5 ka that probably reached the spillover limit ˜100 m. A brief (lake level by 4.6 ka. Evidence from relict Porr strand plain indicate that lake level was probably below 20 m since ca 4.5 ka, though there were two noticeable high stands up to 12-20 m at ca 830 years ago and <100 years, the latter age is consistent with the historic record.

  18. Foraging economics and performance of polar and subpolar Atlantic seabirds

    OpenAIRE

    Croxall, John P.; Briggs, Dirk R.

    1991-01-01

    Seabirds of high latitudes in the North and South Atlantic (chiefly penguins, Procellariformes, alcids, shags, Gannet and Kittiwake) are compared (on absolute and energy-, mass- and time-specific scaled bases) in terms of the rate at which they supply energy to their offspring, the rate of offspring growth, and the duration of the dependence (fledging) period. For a smaller suite of species, time and energy budgets during complete foraging cycles (including time ashore) and while at sea are c...

  19. A 320-year AMM+SOI Index Reconstruction from Historical Atlantic Tropical Cyclone Records

    Science.gov (United States)

    Chenoweth, M.; Divine, D.

    2010-12-01

    Trends in the frequency of North Atlantic tropical cyclones, including major hurricanes, are dominated by those originating in the deep tropics. In addition, these tropical cyclones are stronger when making landfall and their total power dissipation is higher than storms forming elsewhere in the Atlantic basin. Both the Atlantic Meridional Mode (AMM) and El Nino-Southern Oscillation (ENSO) are the leading modes of coupled air-sea interaction in the Atlantic and Pacific, respectively, and have well-established relationships with Atlantic hurricane variability. Here we use a 320-year record of tropical cyclone activity in the Lesser Antilles region of the North Atlantic from historical manuscript and newspaper records to reconstruct a normalized seasonal (July-October) index combining the Southern Oscillation Index (SOI) and AMM employing both the modern analog technique and back-propagation artificial neural networks. Our results indicate that the AMM+SOI index since 1690 shows no long-term trend but is dominated by both short-term (<10 years) and long-term (quasi-decadal to bi-decadal) variations. The decadal-scale variation is consistent with both instrumental and proxy records elsewhere from the global tropics. Distinct periods of high and low index values, corresponding to high and low tropical cyclone frequency, are regularly-appearing features in the record and provides further evidence that natural decadal -scale variability in Atlantic tropical cyclone frequency must be accounted for when determining trends in records and attribution of climate change.

  20. Functional differences in the backward shifts of CA1 and CA3 place fields in novel and familiar environments.

    Directory of Open Access Journals (Sweden)

    Eric D Roth

    Full Text Available Insight into the processing dynamics and other neurophysiological properties of different hippocampal subfields is critically important for understanding hippocampal function. In this study, we compared shifts in the center of mass (COM of CA3 and CA1 place fields in a familiar and completely novel environment. Place fields in CA1 and CA3 were simultaneously recorded as rats ran along a closed loop track in a familiar room followed by a session in a completely novel room. This process was repeated each day over a 4-day period. CA3 place fields shifted backward (opposite to the direction of motion of the rat only in novel environments. This backward shift gradually diminished across days, as the novel environment became more familiar with repeated exposures. Conversely, CA1 place fields shifted backward across all days in both familiar and novel environments. Prior studies demonstrated that CA1 place fields on average do not exhibit a backward shift during the first exposure to an environment in which the familiar cues are rearranged into a novel configuration, although CA3 place fields showed a strong backward shift. Under the completely novel conditions of the present study, no dissociation was observed between CA3 and CA1 during the first novel session (although a strong dissociation was observed in the familiar sessions and the later novel sessions. In summary, this is the first study to use simultaneous recordings in CA1 and CA3 to compare place field COM shift and other associated properties in truly novel and familiar environments. This study further demonstrates functional differentiation between CA1 and CA3 as the plasticity of CA1 place fields is affected differently by exposure to a completely novel environment in comparison to an altered, familiar environment, whereas the plasticity of CA3 place fields is affected similarly during both types of environmental novelty.

  1. Flood magnitudes in the Tagus River (Iberian Peninsula) and its stochastic relationship with daily North Atlantic Oscillation since mid-19th Century

    Science.gov (United States)

    Salgueiro, Ana Rita; Machado, Maria J.; Barriendos, Mariano; Pereira, Henrique Garcia; Benito, Gerardo

    2013-10-01

    This paper presents a new methodological approach in the analysis of the influence of the North Atlantic circulation on the flood magnitude of the Tagus River, the largest Atlantic draining river of the Iberian Peninsula. This methodology is based on Correspondence Analysis viewed as a qualitative regression tool. A daily scale database (sea level atmospheric pressure, river discharge, rainfall) was used for this study. The selected streamflow station, Vila Velha de Rodão (Portugal, near the Spanish border), holds the longest continuous daily river discharge register of the Iberian Peninsula (over 160 years, since 1852). The annual maximum flood magnitudes were classified into seven categories according to their specific recurrence intervals (T). The qualitative regression approach was used to relate annual peak flood occurrence with the North Atlantic Oscillation (NAO) index mode (positive or negative) registered, during the preceding 40 days (divided in 8 successive 5-day periods). Large floods (categories 1-2 of T > 50 years and category 3, T ˜25-50 years) were found to be associated with a very high frequency of the negative NAO mode during the initial 20-25 days (within a total 40 days period length) before de flood peak. The lack of significant association of these flood categories with a predominant NAO mode during the immediately preceding 15 days, prior to the flood, suggest a time lag of 15 days before the peak. Minor flooding (category 7, T dam-regulated regimes (before and after the construction of dams ca 1960) revealed no changes in the behaviour of major floods (responding to a period of 25 days with a dominant negative NAO index mode). Moderate flooding of category 4 (T: 10-25 years), that during the pre-dam construction period were linked to the existence of an initial 5-15 days of negative NAO mode, were not documented during the post-dam period, probably due to flood peak discharge attenuation by reservoirs. The clear climatic control (rainfall

  2. Topological organization of CA3-to-CA1 excitation.

    Science.gov (United States)

    Hongo, Yoshie; Ogawa, Koichi; Takahara, Yuji; Takasu, Keiko; Royer, Sebastien; Hasegawa, Minoru; Sakaguchi, Gaku; Ikegaya, Yuji

    2015-09-01

    The CA1-projecting axons of CA3 pyramidal cells, called Schaffer collaterals, constitute one of the major information flow routes in the hippocampal formation. Recent anatomical studies have revealed the non-random structural connectivity between CA3 and CA1, but little is known regarding the functional connectivity (i.e. how CA3 network activity is functionally transmitted downstream to the CA1 network). Using functional multi-neuron calcium imaging of rat hippocampal slices, we monitored the spatiotemporal patterns of spontaneous CA3 and CA1 burst activity under pharmacological GABAergic blockade. We found that spatially clustered CA3 activity patterns were transformed into layered CA1 activity sequences. Specifically, synchronized bursts initiated from multiple hot spots in CA3 ensembles, and CA1 neurons located deeper in the pyramidal cell layer were recruited during earlier phases of the burst events. The order of these sequential activations was maintained across the bursts, but the sequence velocity varied depending on the inter-burst intervals. Thus, CA3 axons innervate CA1 neurons in a highly topographical fashion. © 2015 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

  3. Witches in the Atlantic World.

    Science.gov (United States)

    Breslaw, Elaine

    2003-01-01

    Presents a lesson plan that focuses on witchcraft in the Atlantic world. Describes each of the four sections of the lesson that encompasses learning about terms and religious views on witchcraft to the history of witchcraft in New England, in the United States, and the Salem (Massachusetts) witchcraft trials. (CMK)

  4. Somatic PIK3CA mutations in seven patients with PIK3CA-related overgrowth spectrum.

    Science.gov (United States)

    Yeung, Kit San; Ip, Janice Jing Kun; Chow, Chin Pang; Kuong, Evelyn Yue Ling; Tam, Paul Kwong-Hang; Chan, Godfrey Chi-Fung; Chung, Brian Hon-Yin

    2017-04-01

    Somatic mutations in PIK3CA cause many overgrowth syndromes that have been recently coined the "PIK3CA-Related Overgrowth Spectrum." Here, we present seven molecularly confirmed patients with PIK3CA-Related Overgrowth Spectrum, including patients with Congenital Lipomatous Overgrowth, Vascular Malformations, Epidermal Nevi, Scoliosis/Skeletal and Spinal syndrome, Klippel-Trenaunay syndrome, lymphatic malformation and two with atypical phenotypes that cannot be classified into existing disease categories. The literature on PIK3CA-Related Overgrowth Spectrum, suggests that PIK3CA c.1258T>C; p.(Cys420Arg), c.1624G>A; p.(Glu542Lys), c.1633G>A; p.(Glu545Lys), c.3140A>G; p.(His1047Arg), and c.3140A>T; p.(His1047Leu) can be identified in approximately 90% of patients without brain overgrowth. Therefore, droplet digital polymerase chain reaction targeting these mutation hotspots could be used as the first-tier genetic test on patients with PIK3CA-Related Overgrowth Spectrum who do not have signs of overgrowth in their central nervous system. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  5. Water level changes for Lake Turkana and climate variability during the African Humid Period

    Science.gov (United States)

    Bloszies, C.; Forman, S. L.; Wright, D. K.

    2013-12-01

    The chronology of East African paleoclimate suggests the transition through the African Humid Period (AHP) at ca. 15 to 5 ka was a binary shift from wet conditions in the Late Pleistocene to current aridity. Previous studies indicate that water levels for Lake Turkana for the AHP were stable at ~88 to 98 m above current level with outflow into the White Nile Basin. This study of relict beaches around Lake Turkana indicates surprisingly >50 m variability in water level between 14 and 4 ka. The elevation of past water level is constrained by barometric and GPS-based altimetry of relict beaches and age control by 14C dating of associated mollusks and OSL dating of quartz grains from surrounding littoral and sublittoral deposits. We also include well provenanced lake level data from prior studies to constrain more fully the timing and height of water level fluctuations in the Late Quaternary. Additionally, previous studies indicate that peak water levels may be regionally amplified by increased precipitation causing overflow into the Lake Turkana Basin from the adjacent Suguta and Chew Bahir basins, particularly during high stands at ca. >8.5 ka and at 6.3 ka. Our analysis of the Lake Turkana strandplain reveals that water level may have varied by × 60 m, potentially reaching the outlet elevation at ca.11.3, 10.3, 9.0, 6.3 and 5.1 ka. There are other possible high stands at ca. 13.0, 8.4, 7.8 and 7.0 ka with limited elevational and age constraints; it is unknown if these lake stands reached the outlet elevation. Evidence from relict strand plains indicate that lake level was probably below 20 m since ca. 4.5 ka, though there were two noticeable high stands up to >12 to 18 m at ca. 830 years ago and lake levels. Inferences on the source of moisture to sustain these many high stands are based on the isotopic data on leaf wax (δDwax) from lakes Tanganika and Victoria and associated sea surface temperature (SST) records from the Indian and the Atlantic oceans. A brief

  6. The Middle to Late Miocene carbonate crash: High resolution XRF core-log examination of ODP Sites 1085 and 1087, SE Atlantic

    Science.gov (United States)

    Bickert, T.; Westerhold, T.; Roehl, U.

    2001-05-01

    In the eastern South Atlantic Ocean the most profound change in Neogene calcium carbonate deposition occurred in the middle to late Miocene (about 12 to 9 Ma), when carbonate mass accumulation rates abruptly dropped. Similar occurences of carbonate dissolution have been recorded in the central and eastern Pacific as well as in the Carribean Sea. This interval has been referred to as the "carbonate crash" by Lyle et al. (1995, ODP 138 Sci. Res.) and was interpreted as a dramatic shoaling of the lysocline due to a reorganization of deep-water circulation by the closure of the Panama Isthmus. Here, we document the changing pattern of carbonate deposition from 12 to 8 Ma using high-resolution XRF core-scanning measurements (Ca, Sr, Fe, Mn) performed every 4 cm downcore. We focuse on ODP Leg 175 Sites 1085 and 1087 sediments retrieved south of the Namibia upwelling area. The Ca and Fe records were spliced together and then used to construct an astronomically calibrated chronology based on orbital tuning. The derived age model documents high sedimentation rates even during intervals of strong dissolution associated with higher terrigenous input from the African continent, delivered by the Oranje River. The high resolution records demonstrate that the interval across the middle to late Miocene transition is characterized by at least four dissolution events, characterized each by a dramatic drop in the carbonate content, a continous period of low carbonate accumulation, and a gradual increase towards normal levels of carbonate deposition. A distinct 41-ky cyclicity of Ca and Fe within the crash interval is followed by a 100-ky period dominance in the time afterwards. The timing of the dissolution events and the periodicity of the sedimentary records are dicussed in terms of global sea-level fluctuations, oceanic changes, and paleoproductivity.

  7. Ground-state correlations in 40Ca and 48Ca

    Science.gov (United States)

    Takayanagi, K.; Lipparini, E.

    1992-01-01

    Second-order perturbation theory with a G-matrix is adopted to examine from a unified point of view the effects of two-particle-two-hole correlations on the matter and momentum distributions and the occupation numbers in 40Ca and 48Ca. Polarization effects induced by the neutron excess in 48Ca are investigated in detail.

  8. Saharan Dust as a Causal Factor of Significant Cloud Cover Along the Saharan Air Layer in the Atlantic Ocean

    Science.gov (United States)

    Kishcha, Pavel; Da Silva, Arlindo M.; Starobinet, Boris; Alpert, Pinhas

    2016-01-01

    The tropical Atlantic is frequently affected by Saharan dust intrusions. Based on MODIS cloud fraction (CF) data during the ten-year study period, we found that these dust intrusions contribute to significant cloud cover along the Saharan Air Layer (SAL). Below the temperature inversion at the SAL's base, the presence of large amounts of settling dust particles, together with marine aerosols, produces meteorological conditions suitable for the formation of shallow stratocumulus clouds. The significant cloud fraction along the SAL together with clouds over the Atlantic Inter-tropical Convergence Zone contributes to the 20% hemispheric CF asymmetry between the tropical North and South Atlantic. This leads to the imbalance in strong solar radiation, which reaches the sea surface between the tropical North and South Atlantic, and, consequently, affects climate formation in the tropical Atlantic. Therefore, despite the fact that, over the global ocean, there is no noticeable hemispheric asymmetry in cloud fraction, over the significant area such as the tropical Atlantic the hemispheric asymmetry in CF takes place. Saharan dust is also the major contributor to hemispheric aerosol asymmetry over the tropical Atlantic. The NASA GEOS-5 model with aerosol data assimilation was used to extend the MERRA reanalysis with five atmospheric aerosol species (desert dust, sulfates, organic carbon, black carbon, and sea-salt). The obtained ten-year (2002 - 2012) MERRA-driven aerosol reanalysis dataset (aka MERRAero) showed that, over the tropical Atlantic, dust and carbonaceous aerosols were distributed asymmetrically relative to the equator, while other aerosol species were distributed more symmetrically.

  9. Drought modulated by North Atlantic sea surface temperatures for the last 3,000 years along the northwestern Gulf of Mexico

    Science.gov (United States)

    Livsey, Daniel; Simms, Alexander R.; Hangsterfer, Alexandra; Nisbet, Robert A.; DeWitt, Regina

    2016-03-01

    In 2012 the most severe United States drought since the 1930's occurred, highlighting the need for a better understanding of the climate factors driving droughts. Spatial-temporal analysis of United States precipitation data from 1900 to 1999 indicates that the Atlantic Multidecadal Oscillation (AMO) primarily modulates drought frequency. Tree rings provide the highest resolution and most spatially distributed drought records beyond secular time-series; however, as most tree-ring records only extend to ca. 1000 years before present (BP), a new broadly distributed, quantitative, multi-millennial, proxy of past drought is needed to determine if the AMO modulated drought across North America through the late Holocene. In this study, we develop a new quantitative drought proxy from a transfer function between X-Ray Fluorescence (XRF) derived elemental data from a Texas playa and a tree-ring drought record. Using this transfer function, a 954-year tree-ring drought record was extended to ca. 3000 BP. Changes in the extended drought record correspond with timing of the Roman Climate Optimum, Medieval Warm Period, Little Ice Age, and changes in the AMO as recorded in a proxy record derived from North Atlantic ice-rafted debris. These results indicate that lacustrine-derived XRF element data can be used as a quantitative tool to reconstruct past drought records, and suggest that AMO modulated drought in southern Texas for the last 3000 years. Additional studies using XRF-derived element data as a drought proxy are needed to determine the utility of this proxy in non-playa lacustrine systems.

  10. Summer North Atlantic Oscillation and flood variability in Switzerland

    Science.gov (United States)

    Peña, Juan Carlos; Schulte, Lothar; Badoux, Alexandre

    2016-04-01

    The study analyses the possible links between flood frequency in Switzerland and the North Atlantic dynamics over the last two centuries. Given the intricate topography of Switzerland, it will generate a territorial division to retain main physiographic and environmental dissimilarities between different regions. The flood variability in Switzerland over the period 1800-2010 has been determined from a flood damage index for July and August months. The index considers very severe and catastrophic floods from existing flood inventories, summarizing both the severity of these events, their spatial extent and the regional differences. Special attention will be focused on the disparities between flood dynamics at northern and southern slopes of the Alps. The analysis of the possible links between floods and North Atlantic dynamics is focused on the low-frequency atmospheric circulation patterns. Summer climate in the North Atlantic-European sector shows a principal pattern of year-to-year variability, although this pattern is weaker than the North Atlantic Oscillation (NAO) in winter and is confined to northern latitudes. By analogy the climatology community refers to this pattern as the Summer North Atlantic Oscillation (SNAO), which is defined as the main empirical orthogonal function of the standardized anomalies of the European mean sea level pressure during July and August. The flood damage index provides evidences of floods clusters in: 1830-1851, 1881-1927, 1977-1990 and 2005 to present. These clusters coincide with those reported from Switzerland and from some areas of the European continent such as the Czech Republic, Italy and the eastern half of the Iberian Peninsula. This link is not so close when compared with the flood occurrences in Germany. The analysis of the principal mode of low-frequency atmospheric variability shows that the Swiss river catchments situated on the center and southern flank of the Alps are affected by atmospherically unstable areas

  11. Solar Influence on the North Atlantic Oscillation - Initial Results

    CERN Document Server

    Dacie, Sally

    2015-01-01

    Some initial investigations into various atmospheric phenomena and the influence of the solar cycle on weather have been made. Strongly negative North Atlantic Oscillation (NAO) indices, which cause cold and dry winter weather in North West Europe, rarely occur during periods of high solar activity. Coupling between the troposphere and stratosphere is discussed, particularly in the context of Polar-night jet oscillation events (defined by Hitchcock et al., 2013) and the Quasi-Biennial Oscillation. The energy of North Atlantic hurricanes (as indicated by the Accumulated Cyclone Energy Index, ACE) is also linked to solar activity, via UV heating at the tropopause (Elsner et al., 2010), and is suggested as a possible mechanism through which solar activity could influence the NAO. Finally the lack of solar influence on the NAO before $\\sim$ 1950 is addressed, with a possible cause being the smaller solar cycle amplitudes. This short report contains several ideas, which may be worth pursuing further.

  12. Water Mass Variability at the Mid-Atlantic Ridge and in the Eastern North Atlantic

    Science.gov (United States)

    Köllner, Manuela; Klein, Birgit; Kieke, Dagmar; Klein, Holger; Roessler, Achim; Rhein, Monika

    2017-04-01

    The strong warming and salinification of the Eastern North Atlantic starting in the mid 1990s has been attributed to a westward contraction of the sub-polar gyre and stronger inflow of waters from the sub-tropical gyre. Temporal changes in the shape and strength of the two gyres have been related to the major mode of atmospheric variability in the Atlantic sector, the NAO. Hydrographic conditions along the Northwest European shelf are thus the result of different processes such as variations in transports, varying relative contributions of water masses from the two gyres and property trends in the source water masses. The North Atlantic Current (NAC) can be regarded as the southern border of the sub-polar gyre transporting water from the tropical regions northward. On its way towards the Mid Atlantic Ridge (MAR) the NAC has partly mixed with waters from the sub-polar gyre and crosses the MAR split into several branches. For the study we analyzed data of water mass variability and transport fluctuations from the RACE (Regional circulation and Global change) project (2012-2015) which provided time series of transports and hydrographic anomalies from moored instruments at the western flank of the MAR. The time depending positions of the NAC branches over the MAR were obtained from mooring time series and compared to sea surface velocities from altimeter data. The results show a high variability of NAC pathways over the MAR. Transition regimes with strong meandering and eddies could be observed as well as periods of strong NAC branches over the Fracture Zones affecting water mass exchange at all depth levels. A positive temperature trend at depths between 1000-2000 m was found at the Faraday Fracture Zone (FFZ). This warming trend was also detected by Argo floats crossing the MAR close to the FFZ region. During the second phase of RACE (RACE-II, 2016-2018) a mooring array across the eastern shelf break at Goban Spur was deployed to monitor the poleward Eastern Boundary

  13. The role of Atlantic overturning circulation in the recent decline of Atlantic major hurricane frequency

    OpenAIRE

    Yan, Xiaoqin; Zhang, Rong; Knutson, Thomas R.

    2017-01-01

    Observed Atlantic major hurricane frequency has exhibited pronounced multidecadal variability since the 1940s. However, the cause of this variability is debated. Using observations and a coupled earth system model (GFDL-ESM2G), here we show that the decline of the Atlantic major hurricane frequency during 2005–2015 is associated with a weakening of the Atlantic Meridional Overturning Circulation (AMOC) inferred from ocean observations. Directly observed North Atlantic sulfate aerosol optical ...

  14. Abrupt changes in Antarctic Intermediate Water strength lead Atlantic Meridional Overturning Circulation changes during the last deglacial

    Science.gov (United States)

    Xie, R.; Marcantonio, F.; Schmidt, M. W.

    2011-12-01

    Reorganization of meridional overturning circulation that is a response to or a trigger of climate change in the North Atlantic has been a subject of intense interest. During the last deglaciation, cold periods such as the Younger Dryas (YD) and Heinrich 1 (H1) are thought to be coincident with significant reductions in North Atlantic Deep Water (NADW) formation. Yet, the role that Antarctic Intermediate Water (AAIW) played during these cold events is still poorly constrained. Benthic Cd/Ca data from sediment cores in the Florida Straits suggest a reduced contribution of AAIW in the North Atlantic western boundary current during the YD [1]. However, ɛNd evidence in sediment cores from Tobago basin suggests a greater influence of AAIW in the North Atlantic during YD and H1 [2]. In this study, we measure ɛNd values in the authigenic Fe-Mn oxyhydroxide fraction of sediment from three cores, KNR166-2-26JPC (24°19.62'N, 83°15.14'W; 546 m) and KNR166-2-31JPC (24°13.18'N, 83°17.75'W; 751 m) within the Florida Straits, and VM12-107 (11.33°N, 66.63°W; 1079 m) in the Southern Carribean Sea. All three cores lie within the path of AAIW and are, therefore, useful to gauge the waxing and waning of AAIW during the last deglaciation. Cores 26JPC and 31JPC are located within the Florida Current, which under modern conditions represents a mixture of recirculated North Atlantic subtropical gyre water and Southern origin waters. Our preliminary results from 26JPC and 31JPC show significantly less radiogenic ɛNd values during the YD and H1 than during the Holocene (~1 epsilon unit for 26JPC and ~0.6 epsilon units for 31JPC during both periods). We interpret the lower ɛNd during the YD and H1 as signifying a decreased input of Southern-sourced waters (i.e., AAIW) arriving at these sites, in agreement with the study of Came et al.[1], but not that of Pahnke et al. in the Tobago Basin [2]. We suggest that ɛNd values in the latter study, in which the core site location is at a

  15. 76 FR 45781 - Atlantic Highly Migratory Species; Meeting of the Atlantic Highly Migratory Species Advisory Panel

    Science.gov (United States)

    2011-08-01

    ... National Oceanic and Atmospheric Administration RIN 0648-XA573 Atlantic Highly Migratory Species; Meeting of the Atlantic Highly Migratory Species Advisory Panel AGENCY: National Marine Fisheries Service... meeting. SUMMARY: NMFS will hold a 3-day Atlantic Highly Migratory Species (HMS) Advisory Panel (AP...

  16. 75 FR 44938 - Atlantic Coastal Fisheries Cooperative Management Act Provisions; Atlantic Coastal Shark Fishery

    Science.gov (United States)

    2010-07-30

    ... 0648-XX28 Atlantic Coastal Fisheries Cooperative Management Act Provisions; Atlantic Coastal Shark... cancellation of the Federal moratorium on fishing for Atlantic coastal sharks in the State waters of New Jersey... Sharks (Coastal Shark Plan). DATES: Effective July 30, 2010. ADDRESSES: Emily Menashes, Acting Director...

  17. 76 FR 57709 - Atlantic Highly Migratory Species; Atlantic Shark Management Measures

    Science.gov (United States)

    2011-09-16

    ... Species; Atlantic Shark Management Measures AGENCY: National Marine Fisheries Service (NMFS), National... Atlantic shark landings; request for comments. SUMMARY: This notice announces the National Marine Fisheries... Atlantic shark fisheries. NMFS published an Advanced Notice of Proposed Rulemaking (ANPR) on September 20...

  18. 76 FR 67121 - Atlantic Highly Migratory Species; 2012 Atlantic Shark Commercial Fishing Season

    Science.gov (United States)

    2011-10-31

    ... Species; 2012 Atlantic Shark Commercial Fishing Season AGENCY: National Marine Fisheries Service (NMFS... season for the Atlantic commercial shark fisheries. Quotas would be adjusted based on any over- and/or underharvests experienced during the 2010 and 2011 Atlantic commercial shark fishing seasons. In addition, NMFS...

  19. 77 FR 61562 - Atlantic Highly Migratory Species; 2013 Atlantic Shark Commercial Fishing Season

    Science.gov (United States)

    2012-10-10

    ... Species; 2013 Atlantic Shark Commercial Fishing Season AGENCY: National Marine Fisheries Service (NMFS... season for the Atlantic commercial shark fisheries. Quotas would be adjusted as allowable based on any over- and/or underharvests experienced during the 2011 and 2012 Atlantic commercial shark fishing...

  20. Diel variation in feeding and movement patterns of juvenile Atlantic cod at offshore wind farms

    Science.gov (United States)

    Reubens, Jan T.; De Rijcke, Maarten; Degraer, Steven; Vincx, Magda

    2014-01-01

    Atlantic cod (Gadus morhua) is a commercially important fish species suffering from overexploitation in the North-East Atlantic. In recent years, their natural environment is being intensively altered by the construction of offshore wind farms in many coastal areas. These constructions form artificial reefs influencing local biodiversity and ecosystem functioning. It has been demonstrated that Atlantic cod is present in the vicinity of these constructions. However, empirical data concerning the diel activity and feeding behaviour of Atlantic cod in the vicinity of these artificial reefs is lacking. Atlantic cod has a flexible diel activity cycle linked to spatio-temporal variations in food availability and predation risk. In this study we integrated acoustic telemetry with stomach content analysis to quantify diel activity and evaluate diel feeding patterns at a windmill artificial reef (WAR) in the Belgian part of the North Sea. Atlantic cod exhibited crepuscular movements related to feeding activity; a 12 h cycle was found and the highest catch rates and stomach fullness were recorded close to sunset and sunrise. It is suggested that the observed diel movement pattern is related to the prey species community and to predation pressure. Foraging at low ambient light levels (i.e. at dusk and dawn) probably causes a trade-off between foraging success and reducing predation pressure. Fish did not leave the area in-between feeding periods. Hence other benefits (i.e. shelter against currents and predators) besides food availability stimulate the aggregation behaviour at the WARs.

  1. Rapid climate changes in the tropical Atlantic region during the last deglaciation

    Science.gov (United States)

    Hughen, Konrad A.; Overpeck, Jonathan T.; Peterson, Larry C.; Trumbore, Susan

    1996-03-01

    THE climate system is capable of changing abruptly from one stable mode to another1-3. Rapid climate oscillations-in particular the Younger Dryas cold period during the last deglaciation-have long been recognized from records throughout the North Atlantic region4-14, and the distribution of these records at mostly high latitudes suggests that the changes were caused by rapid reorganizations of the North Atlantic thermohaline circulation6,8,10,15. But events far from the North Atlantic region that are synchronous with the Younger Dryas16-19 raise the possibility that a more global forcing mechanism was responsible20. Here we present high-resolution records of laminated sediments of the last deglaciation from the Cariaco basin (tropical Atlantic Ocean) which show many abrupt sub-decade to century-scale oscillations in surface-ocean biological productivity that are synchronous with climate changes at high latitudes. We attribute these productivity variations to changes in or duration of up-welling rate (and hence nutrient supply) caused by changes in trade-wind strength, which is in turn influenced by the thermo-haline circulation through its effect on sea surface temperature6,21. Abrupt climate changes in the tropical Atlantic during the last deglaciation are thus consistent with a North Atlantic circulation forcing mechanism.

  2. Genetic diversity and biogeographical patterns of Caulerpa prolifera across the Mediterranean and Mediterranean/Atlantic transition zone

    KAUST Repository

    Varela-Álvarez, Elena

    2015-01-11

    Knowledge of spatial patterns of genetic differentiation between populations is key to understanding processes in evolutionary history of biological species. Caulerpa is a genus of marine green algae, which has attracted much public attention, mainly because of the impacts of invasive species in the Mediterranean. However, very little is known about the ecological and evolutionary history of the Mediterranean native Caulerpa prolifera, a species which is currently found at sites distributed worldwide. C. prolifera provides a good model to explore the patterns of genetic diversity at different scales across the Mediterranean and Atlantic area. This study aims to investigate the biogeographical patterns of diversity and differentiation of C. prolifera in the Mediterranean, with special focus on the Mediterranean/Atlantic transition zone. We used two nuclear (ITS rDNA and the hypervariable microsatellite locus CaPr_J2) and one chloroplast (tufA) DNA markers on samples of C. prolifera from its entire range. Analyses of 51 sequences of the cpDNA tufA of C. prolifera, 87 ITS2 sequences and genotypes of 788 ramets of C. prolifera for the locus CaPr_J2 revealed three different biogeographical areas: West Atlantic, East Atlantic and a larger area representing the Mediterranean, the Mediterranean/Atlantic transition zone and a Pacific site (Bali). It was found out that the Mediterranean/Atlantic transition zone is a biogeographical boundary for C. prolifera. A lack of connectivity was revealed between Atlantic and Mediterranean types, and identical sequences found in the Mediterranean and Indo-Pacific suggest either recent gene flow along the Red Sea connection or a possible ancient Indo-Pacific origin.

  3. On the Influence of the Pacific and Atlantic Meridional Modes on Precipitation over the Continental United States

    Science.gov (United States)

    Zhang, W.; Villarini, G.; Vecchi, G. A.

    2016-12-01

    The Pacific Meridional Mode (PMM) and the Atlantic Meridional Mode (AMM) are the first Maximum Covariance Analysis (MCA) modes of sea surface temperature (SST) and surface wind fields in the Pacific and North Atlantic. PMM and AMM strongly modulate tropical cyclone activity in the western North Pacific and the North Atlantic, respectively. However, little is known about the role that PMM and AMM play in controlling precipitation across the continental United States. This study examines the impacts of PMM and AMM in terms of total and extreme precipitation. Analyses will be performed at the seasonal scale over the 1948-2015 period. The physical mechanisms responsible for such influences will also be presented.

  4. Summer North Atlantic Oscillation: decadal change, impact, and possible mechanisms

    Science.gov (United States)

    Sun, J.

    2010-12-01

    Summer North Atlantic Oscillation: decadal change, impact, and possible mechanisms Jianqi Sun, Huijun Wang, and Wei Yuan Nansen-Zhu International Research Centre (NZC), Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China. Email: sunjq@mail.iap.ac.cn It is well known that the North Atlantic Oscillation (NAO) is strong in winter, so most previous studies focused on the NAO in winter time. However, actually the NAO is also one of the teleconnection patterns that have a year-round presence. For example, some studies have indicated that the summer North Atlantic Oscillation (SNAO) is still a dominant pattern over the North Atlantic region. So it is of importance to investigate the SNAO’s variability and influences. Our recent studies revealed that the summer (SNAO) experienced a significant decadal change around the late 1970s, with the southern action center located farther eastward after the late 1970s as compared to before. Such decadal change of the SNAO pattern altered its relationship with the Northern Hemispheric summer climate. In the period before the late 1970s, the connection of the SNAO on the Northern Hemispheric land surface air temperature is weak, but after that time the impact of the SNAO is significantly enhanced. Our further analysis indicated that the decadal change of the SNAO pattern is to some extend attributed to the decadal variability of the Mediterranean-Black Sea (MBS) sea surface temperature (SST). In 1951-1975, the variability of the MBS SST is quite weak, but in 1978-2002 it becomes more active. The active MBS SST can enhance the interaction between the sea and its overlying atmosphere, thus strengthening the activity of the east part of the SNAO southern center after the late 1970s and consequently producing an eastward SNAO southern center shift. This observational analysis result is further confirmed by sensitivity experiments. Besides the MBS SST, the decadal variability of the tropical Atlantic SST

  5. The diagnostic value of serum tumor markers CEA, CA19-9, CA125, CA15-3, and TPS in metastatic breast cancer.

    Science.gov (United States)

    Wang, Weigang; Xu, Xiaoqin; Tian, Baoguo; Wang, Yan; Du, Lili; Sun, Ting; Shi, Yanchun; Zhao, Xianwen; Jing, Jiexian

    2017-07-01

    This study aims to understand the diagnostic value of serum tumor markers carcinoembryonic antigen (CEA), cancer antigen 19-9 (CA19-9), cancer antigen 125 (CA125), cancer antigen 15-3 (CA15-3), and tissue polypeptide-specific antigen (TPS) in metastatic breast cancer (MBC). A total of 164 metastatic breast cancer patients in Shanxi Cancer Hospital were recruited between February 2016 and July 2016. 200 breast cancer patients without metastasis in the same period were randomly selected as the control group. The general characteristics, immunohistochemical, and pathological results were investigated between the two groups, and tumor markers were determined. There were statistical differences in the concentration and the positive rates of CEA, CA19-9, CA125, CA15-3, and TPS between the MBC and control group (Pspecificity was in CA125 for the diagnosis of MBC when using a single tumor marker at 56.7% and 97.0%, respectively. In addition, two tumor markers were used for the diagnosis of MBC and the CEA and TPS combination had the highest diagnostic sensitivity with 78.7%, while the CA15-3 and CA125 combination had the highest specificity of 91.5%. Analysis of tumor markers of 164 MBC found that there were statistical differences in the positive rates of CEA and CA15-3 between bone metastases and other metastases (χ 2 =6.00, P=0.014; χ 2 =7.32, P=0.007, respectively). The sensitivity and specificity values of the CEA and CA15-3 combination in the diagnosis of bone metastases were 77.1% and 45.8%, respectively. The positive rate of TPS in the lung metastases group was lower than in other metastases (χ 2 =8.06, P=0.005).There were significant differences in the positive rates of CA15-3 and TPS between liver metastases and other metastases (χ 2 =15.42, Pspecificity of the CA15-3 and TPS combination in the diagnosis of liver metastases were 92.3% and 45.6%, respectively, and the positive rate of CEA in triple-negative metastatic breast cancer is lower than in other

  6. Triassic - Jurassic kinematic relationships between the Gulf of Mexico, Central Atlantic Ocean, and Mexico

    Science.gov (United States)

    Bird, D. E.; Burke, K.; Hall, S. A.; Casey, J. F.

    2008-05-01

    Closing ocean basins along geomagnetic isochrons can be an objective method for analyzing reconstructed continental margins because, in general, tectonic extension at passive margins stops once new oceanic lithosphere is created. Holding Africa fixed, we close the South Atlantic Ocean to Chron M4 (126.6 Ma) and the Central Atlantic Ocean to Chron M40 (165.1 Ma). In this configuration, and with the Gulf of Mexico closed by clockwise rotation of the Yucatan continental block (~42 degrees), the positions of North America and South America indicate that the Gulf of Mexico opened at least 20 My after the opening of the Central Atlantic Ocean (ca. 180 Ma) and the earlier breakup of Pangea (ca. 200 Ma). The Gondwanan terranes of eastern Mexico, Yucatan, Florida, and the United States south of the Ouachita-Marathon Suture, remained attached to Laurasia after the breakup of the supercontinent. The Gulf of Mexico then formed in Late Jurassic to earliest Cretaceous times (ca. 160 Ma to 140 Ma) by counterclockwise rotation of the Yucatan block. Two prominent basement structures, defined by seismic refraction and gravity data, are interpreted to be hotspot tracks created by a single mantle plume during this rotation. A third prominent basement structure is interpreted to be a marginal ridge that developed along the ocean-continental transform boundary between the Yucatan block and eastern Mexico. The Gulf of Mexico formed after initial rifting and extension of continental crust and widespread salt deposition (ca. 160 Ma to 150 Ma), followed by the mantle plume eruption and sea-floor spreading (ca. 150 Ma to 140 Ma).

  7. Divergence of Ca(2+) selectivity and equilibrium Ca(2+) blockade in a Ca(2+) release-activated Ca(2+) channel.

    Science.gov (United States)

    Yamashita, Megumi; Prakriya, Murali

    2014-03-01

    Prevailing models postulate that high Ca(2+) selectivity of Ca(2+) release-activated Ca(2+) (CRAC) channels arises from tight Ca(2+) binding to a high affinity site within the pore, thereby blocking monovalent ion flux. Here, we examined the contribution of high affinity Ca(2+) binding for Ca(2+) selectivity in recombinant Orai3 channels, which function as highly Ca(2+)-selective channels when gated by the endoplasmic reticulum Ca(2+) sensor STIM1 or as poorly Ca(2+)-selective channels when activated by the small molecule 2-aminoethoxydiphenyl borate (2-APB). Extracellular Ca(2+) blocked Na(+) currents in both gating modes with a similar inhibition constant (Ki; ~25 µM). Thus, equilibrium binding as set by the Ki of Ca(2+) blockade cannot explain the differing Ca(2+) selectivity of the two gating modes. Unlike STIM1-gated channels, Ca(2+) blockade in 2-APB-gated channels depended on the extracellular Na(+) concentration and exhibited an anomalously steep voltage dependence, consistent with enhanced Na(+) pore occupancy. Moreover, the second-order rate constants of Ca(2+) blockade were eightfold faster in 2-APB-gated channels than in STIM1-gated channels. A four-barrier, three-binding site Eyring model indicated that lowering the entry and exit energy barriers for Ca(2+) and Na(+) to simulate the faster rate constants of 2-APB-gated channels qualitatively reproduces their low Ca(2+) selectivity, suggesting that ion entry and exit rates strongly affect Ca(2+) selectivity. Noise analysis indicated that the unitary Na(+) conductance of 2-APB-gated channels is fourfold larger than that of STIM1-gated channels, but both modes of gating show a high open probability (Po; ~0.7). The increase in current noise during channel activation was consistent with stepwise recruitment of closed channels to a high Po state in both cases, suggesting that the underlying gating mechanisms are operationally similar in the two gating modes. These results suggest that both high affinity Ca

  8. North Atlantic early 20th century warming and impact on European summer: Mechanisms and Predictability

    Science.gov (United States)

    Müller, Wolfgang

    2017-04-01

    . Lohmann,G. P. Compo, and J. Marotzke, 2015: A 20th-century reanalysis forced ocean model to reconstruct North Atlantic climate variation during the 1920s, Climate Dynamics. doi:10.1007/s00382-014-2267-5 Müller, W. A., H. Pohlmann, F. Sienz, and D. Smith, 2014: Decadal climate prediction for the period 1901-2010 with a coupled climate model. Geophys. Res. Lett., 41, pp 2100-2107.

  9. A randomised, family-focused dietary intervention to evaluate the Atlantic diet: the GALIAT study protocol.

    Science.gov (United States)

    Calvo-Malvar, Maria Del Mar; Leis, Rosaura; Benítez-Estévez, Alfonso Javier; Sánchez-Castro, Juan; Gude, Francisco

    2016-08-18

    The traditional diet of northwestern Spain and northern Portugal follows an 'Atlantic diet' pattern. Adherence to the Atlantic diet has been related to the good metabolic health and low coronary mortality recorded for these regions. The GALIAT (Galicia Alimentación Atlántica [Galicia Atlantic Diet]) study is a randomised, controlled, dietary intervention clinical trial designed to examine the effect of the Atlantic diet on the lipid profile, glucose metabolism, inflammation makers and adiposity of the general population. The trial involved 250 randomly selected families (715 adults and children over 3 years of age) from a town in Spain's northwest, randomly allocated to follow either a control diet (C group) or the Atlantic diet (AD group) for a period of 6 months. The families of the AD group received educational sessions on food, diet and gastronomy and were provided written supporting material with nutritional recommendations and recipes for the preparation of menus. They also attended cooking classes. Throughout the study period, these families were provided a range of foods (free of charge) that form part of the traditional Atlantic diet. The C group families took part in none of the above activities, nor were they provided with any food. Lipid profile variables (primary variables), and anthropometric, inflammation marker and glucose metabolism status (secondary variables), were measured at baseline, three and six months. The GALIAT study is the first clinical trial to examine the effects of the Atlantic diet on metabolic and cardiovascular health and adiposity. If the study hypothesis is confirmed, this dietary pattern could be included in strategies to promote health. ClinicalTrials.gov, NCT02391701 on March 18, 2015.

  10. A randomised, family-focused dietary intervention to evaluate the Atlantic diet: the GALIAT study protocol

    Directory of Open Access Journals (Sweden)

    Maria del Mar Calvo-Malvar

    2016-08-01

    Full Text Available Abstract Background The traditional diet of northwestern Spain and northern Portugal follows an ‘Atlantic diet’ pattern. Adherence to the Atlantic diet has been related to the good metabolic health and low coronary mortality recorded for these regions. Methods The GALIAT (Galicia Alimentación Atlántica [Galicia Atlantic Diet] study is a randomised, controlled, dietary intervention clinical trial designed to examine the effect of the Atlantic diet on the lipid profile, glucose metabolism, inflammation makers and adiposity of the general population. The trial involved 250 randomly selected families (715 adults and children over 3 years of age from a town in Spain’s northwest, randomly allocated to follow either a control diet (C group or the Atlantic diet (AD group for a period of 6 months. The families of the AD group received educational sessions on food, diet and gastronomy and were provided written supporting material with nutritional recommendations and recipes for the preparation of menus. They also attended cooking classes. Throughout the study period, these families were provided a range of foods (free of charge that form part of the traditional Atlantic diet. The C group families took part in none of the above activities, nor were they provided with any food. Lipid profile variables (primary variables, and anthropometric, inflammation marker and glucose metabolism status (secondary variables, were measured at baseline, three and six months. Discussion The GALIAT study is the first clinical trial to examine the effects of the Atlantic diet on metabolic and cardiovascular health and adiposity. If the study hypothesis is confirmed, this dietary pattern could be included in strategies to promote health. Trial registration ClinicalTrials.gov, NCT02391701 on March 18, 2015.

  11. Does nutrient cycling differ between fragments of Atlantic Forest with distinct structural aspects? A case study in the state of Rio de Janeiro, Brazil

    Directory of Open Access Journals (Sweden)

    Gláucio de Mello Cunha

    2014-12-01

    Full Text Available In this study, we evaluate litter biomass and nutrient inputs, as well as nutrient use efficiency (NUE, in two fragments of dense montane rain forest within the Atlantic Forest Biome in the northern region of the state of Rio de Janeiro, Brazil. The total annual average litter production for the two fragments (designated M1 and M2 was 7.72 and 7.56 t ha−¹ year−¹, respectively. The annual nutrient return rate was 146.67, 4.84, 21.41, 64.93, and 17.25 kg ha−¹ year−¹ for N, P, K, Ca, and Mg, respectively. No differences in NUE were observed between the studied fragments, except for that of P. The average NUE for N, P, K, Ca, and Mg, respectively, was 51, 1426, 367, 111, and 428 in fragment M1, compared with 51, 1890, 360, 126, and 472 in fragment M2. The litter biomass input did not differ between the forest fragments studied, indicating that the differences in elevation and forest biomass did not affect nutrient cycling. However, a difference in the litter deposition rate between the dry and rainy periods was observed in fragment M2.

  12. Teaching Atlantic Studies in American High Schools.

    Science.gov (United States)

    Foster, Charles R.

    1980-01-01

    Stresses the importance of Atlantic studies within the framework of United States history, European history, and the contemporary world scene. Ways of integrating Atlantic studies into the high school social studies curriculum are suggested. Topics discussed include objectives, audiovisual aids, supplementary reading material, and global political…

  13. The Red Atlantic: Transoceanic Cultural Exchanges

    Science.gov (United States)

    Weaver, Jace

    2011-01-01

    The development of David Armitage's "white Atlantic" history parallels the Cold War origins of American studies with its mission to define and promote "American culture" or "American civilization." British scholar Paul Gilroy's "The Black Atlantic" served as a necessary corrective. Armitage's statement leads…

  14. Absent menstrual periods - primary

    Science.gov (United States)

    Primary amenorrhea; No periods - primary; Absent periods - primary; Absent menses - primary; Absence of periods - primary ... nutrition Tumors In many cases, the cause of primary amenorrhea is not known.

  15. Extracellular glucose supports lactate production but not aerobic metabolism in cardiomyocytes from both normoglycemic Atlantic cod and low glycemic short-horned sculpin.

    Science.gov (United States)

    Clow, Kathy A; Short, Connie E; Driedzic, William R

    2016-05-01

    Fish exhibit a wide range of species-specific blood glucose levels. How this relates to glucose utilization is yet to be fully realized. Here, we assessed glucose transport and metabolism in myocytes isolated from Atlantic cod (Gadus morhua) and short-horned sculpin (Myoxocephalus scorpius), species with blood glucose levels of 3.7 and 0.57 mmol l(-1), respectively. Glucose metabolism was assessed by the production of (3)H2O from [2-(3)H]glucose. Glucose metabolism was 3.5- to 6-fold higher by myocytes from Atlantic cod than by those from short-horned sculpin at the same level of extracellular glucose. In Atlantic cod myocytes, glucose metabolism displayed what appears to be a saturable component with respect to extracellular glucose, and cytochalasin B inhibited glucose metabolism. These features revealed a facilitated glucose diffusion mechanism that accounts for between 30% and 55% of glucose entry at physiological levels of extracellular glucose. Facilitated glucose diffusion appears to be minimal in myocytes for short-horned sculpin. Glucose entry by simple diffusion occurs in both cell types with the same linear relationship between glucose metabolism and extracellular glucose concentration, presumably due to similarities in membrane composition. Oxygen consumption by myocytes incubated in medium containing physiological levels of extracellular glucose (Atlantic cod 5 mmol l(-1), short-horned sculpin 0.5 mmol l(-1)) was similar in the two species and was not decreased by cytochalasin B, suggesting that these cells have the capability of oxidizing alternative on-board metabolic fuels. Cells produced lactate at low rates but glycogen levels did not change during the incubation period. In cells from both species, glucose utilization assessed by both simple chemical analysis of glucose disappearance from the medium and (3)H2O production was half the rate of lactate production and as such extracellular glucose was not available for oxidative metabolism

  16. EFFLUENT - DISCHARGE DESCRIPTION and Other Data from FIXED PLATFORM and Other Platforms From NW Atlantic (limit-40 W) from 19800529 to 19840609 (NODC Accession 8600070)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Effluent discharge was studied from fixed platform and other platforms from NW Atlantic (limit-40 w) for a period of three years. The trace metal concentrations were...

  17. WATER TEMPERATURE and other data from VREELAND in the TOGA Area - Atlantic from 1990-06-12 to 1990-07-01 (NCEI Accession 9000193)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data in this accession was collected from TOGA Area, Atlantic aboard ship Vreeland over two week period between June 12 to July 1, 1990. The real time data of...

  18. Cloud amount/frequency, NITRATE and other data from MARION DUFRESNE in the NE Atlantic from 1987-01-14 to 1987-02-13 (NCEI Accession 9000275)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Conductivity, Temperature and Depth (CTD) and other data were collected over one month period from NE Atlantic (limit-40 W) using Ship Marion Dufresne during...

  19. Parietaria pollinosis in an Atlantic area: clinical and palynological data.

    Science.gov (United States)

    Vidal, C; Dopazo, A; Aira, M J

    2001-01-01

    Parietaria pollen is considered as one of the most common causes of allergic respiratory symptoms in the Mediterranean area but its presence is limited in the Atlantic area. Some leading patients from Muros, a small town on the Spanish Atlantic coast, complaining of nearly all year round respiratory symptoms happened to be allergic to Parietaria pollen. To evaluate the prevalence of Parietaria sensitization among patients from this Atlantic town, and its correlation with aerobiological data (concentration of Urticaceae pollen). Eighty-nine patients suffering from rhinoconjunctivitis and/or asthma from the area of Muros between January 1998 and January 1999 were included. Skin prick tests and serum-specific IgE (CAP Pharmacia) to Parietaria judaica and a battery of perennial or seasonal allergens were performed. Information about the seasonal and hourly rhythm of symptoms was obtained in each patient sensitized to Parietaria pollen. Atmospheric pollen was collected, using a Hirst-type volumetric pollen sampler, during 1998. Parietaria allergy was detected in 22 patients (25%) and represented the second most important aeroallergen after mites and along with grass pollen. The total atmospheric pollen recorded in Muros during the study period was 27,515 pollen grains, Urticaceae being the most important one (18,554 grains, 67% of the total). The proportion of Urticaceae pollen found in Muros was the highest among all samplers belonging to the Spanish Aerobiology Network. Maximum values of Urticaceae pollen were recorded during May and June. Intradiurnal variation of pollen counts showed maximum values between 11 a.m. and 1 p.m. A parallelism was observed between the rate of symptomatic patients and Parietaria type grain pollen count. The prevalence of Parietaria pollen sensitization seems to be very important in this Atlantic area. The presence of very high levels of this pollen in its atmosphere explains this fact. Such sensitization should be taken into account

  20. The Atlantic diet – Origin and features

    Directory of Open Access Journals (Sweden)

    Manuela L. Vaz-Velho

    2016-04-01

    Full Text Available Despite globalization there still are food patterns which are clearly differentiated from one region to another in Europe and elsewhere.  In this study the Atlantic Diet is considered as thetraditional diet in Portugal and Galicia, a regionin northwest Spain.This paper aims to contribute to a better understanding of the Atlantic Diet food pattern in order to fully exploit the potential of this Atlantic gastronomical heritage.The background of the Atlantic Diet concept, the characterization of Atlantic Diet foods and a compilation of scientific findings related to the consumption of these foods are covered.A brief description of the Mediterranean Diet, the primitive pattern and the updated Mediterranean pyramid are also included in order to aid understanding of the globalization of this previously local health food pattern.Final remarks and suggestions for further studies are made.

  1. Inter-Colony Fidelity of Sr/Ca Variability in the Massive Caribbean Coral Siderastrea siderea: a Sub-Fossil Example

    Science.gov (United States)

    Maupin, C. R.; Quinn, T. M.; Poore, R. Z.; Lin, K.; Shen, C.

    2008-12-01

    Coral-based reconstructions of climate variability in the Atlantic Warm Pool (AWP) in the pre-instrumental period are sparse. Multi-century Sr/Ca records generated from the skeleton of the widely distributed, massive, slow growing (~0.5 cm yr-1) coral Siderastrea siderea have the potential to address this data gap by providing robust proxies of interannual- to centennial-scale sea surface temperature (SST) variability in the AWP. However, before modern and fossil geochemical time series from S. siderea can be interpreted in terms of climate variability, reproducibility tests must be performed on individual coral colonies from the same location. Here we provide one such assessment of inter-colony reproducibility in the geochemistry of S. siderea using cores from the Dry Tortugas National Park (~24°33'N, 82°53'W). Time series of Sr/Ca from a large colony cored live in the summer of 1993 and a second, sub-fossil colony core, with a high-precision mass spectrometric U/Th date of 110 ± 1.7 (2σ) yrs, are compared. The 25-year overlap exhibits excellent reproducibility in both monthly and monthly anomaly space, and the average absolute difference between monthly data from the two time series is within instrumental precision. The results of this work suggest that individual monthly Sr/Ca records from S. siderea can be deemed representative of local SST variability, and that continuous local Sr/Ca records can be successfully spliced together from living and sub-fossil corals using high precision U/Th dating.

  2. Sodium-potassium dependent adenosine triphosphatase activity in gills and kidneys of Atlantic salmon (Salmo salar)

    Science.gov (United States)

    McCartney, T.H.

    1976-01-01

    1. Gill and kidney ATPase activities of 2-year-old Atlantic salmon (Salmo salar) were determined periodically from March to July.2. Na-K ATPase activity increased in the gill and declined in the kidney during the time encompassing transformation of parr to smolt under hatchery conditions.

  3. Distribution and drift of Atlantic cod ( Gadus morhua ) eggs and larvae in Greenland offshore waters

    DEFF Research Database (Denmark)

    Wieland, Kai; Hovgård, Holger

    2002-01-01

    Catches of Atlantic cod (Gadus morhua) eggs and larvae from 45 national and international ichthyoplankton surveys conducted in Greenland offshore waters during the period 1950 to 1984 have been compiled and re-analysed. Southeast and Southwest Greenland were identified as im- portant spawning are...

  4. Probabilistic Tsunami Hazard in the Northeast Atlantic from Near- and Far-Field Tectonic Sources

    Science.gov (United States)

    Omira, R.; Baptista, M. A.; Matias, L.

    2015-03-01

    In this article, we present the first study on probabilistic tsunami hazard assessment for the Northeast (NE) Atlantic region related to earthquake sources. The methodology combines the probabilistic seismic hazard assessment, tsunami numerical modeling, and statistical approaches. We consider three main tsunamigenic areas, namely the Southwest Iberian Margin, the Gloria, and the Caribbean. For each tsunamigenic zone, we derive the annual recurrence rate for each magnitude range, from Mw 8.0 up to Mw 9.0, with a regular interval, using the Bayesian method, which incorporates seismic information from historical and instrumental catalogs. A numerical code, solving the shallow water equations, is employed to simulate the tsunami propagation and compute near shore wave heights. The probability of exceeding a specific tsunami hazard level during a given time period is calculated using the Poisson distribution. The results are presented in terms of the probability of exceedance of a given tsunami amplitude for 100- and 500-year return periods. The hazard level varies along the NE Atlantic coast, being maximum along the northern segment of the Morocco Atlantic coast, the southern Portuguese coast, and the Spanish coast of the Gulf of Cadiz. We find that the probability that a maximum wave height exceeds 1 m somewhere in the NE Atlantic region reaches 60 and 100 % for 100- and 500-year return periods, respectively. These probability values decrease, respectively, to about 15 and 50 % when considering the exceedance threshold of 5 m for the same return periods of 100 and 500 years.

  5. Evolution of periodicity in periodical cicadas.

    Science.gov (United States)

    Ito, Hiromu; Kakishima, Satoshi; Uehara, Takashi; Morita, Satoru; Koyama, Takuya; Sota, Teiji; Cooley, John R; Yoshimura, Jin

    2015-09-14

    Periodical cicadas (Magicicada spp.) in the USA are famous for their unique prime-numbered life cycles of 13 and 17 years and their nearly perfectly synchronized mass emergences. Because almost all known species of cicada are non-periodical, periodicity is assumed to be a derived state. A leading hypothesis for the evolution of periodicity in Magicicada implicates the decline in average temperature during glacial periods. During the evolution of periodicity, the determinant of maturation in ancestral cicadas is hypothesized to have switched from size dependence to time (period) dependence. The selection for the prime-numbered cycles should have taken place only after the fixation of periodicity. Here, we build an individual-based model of cicadas under conditions of climatic cooling to explore the fixation of periodicity. In our model, under cold environments, extremely long juvenile stages lead to extremely low adult densities, limiting mating opportunities and favouring the evolution of synchronized emergence. Our results indicate that these changes, which were triggered by glacial cooling, could have led to the fixation of periodicity in the non-periodical ancestors.

  6. /sup 40/Ca-/sup 48/Ca isotope shift

    Energy Technology Data Exchange (ETDEWEB)

    Khodel, V.A.; Platonov, A.P.; Saperstein, E.E. (Gosudarstvennyj Komitet po Ispol' zovaniyu Atomnoj Ehnergii SSSR, Moscow. Inst. Atomnoj Ehnergii)

    1982-07-01

    Contributions of the virtual low-lying collective excitations to the nuclear density are calculated within the framework of the theory of self-consistent finite Fermi systems. It is shown that this effect is responsible for the /sup 40/Ca-/sup 48/Ca isotope shift.

  7. Acanthoecid choanoflagellates from the Atlantic Arctic Region - a baseline study

    DEFF Research Database (Denmark)

    Thomsen, Helge Abildhauge; Østergaard, Jette Buch

    2017-01-01

    The examination and statistical analysis of loricate choanoflagellate material collected from Greenland waters during the period 1988-1998 represents a de facto baseline study of heterotrophic nanoflagellates from the Atlantic Arctic Region. The geographic sites sampled are Disko Bay (West...... Greenland) and the high-arctic North-East Water (NEW) and North Water (NOW) polynya. The analyses encompass close to 50 taxa. Some of these are described as new species, i.e. Acanthocorbis glacialis, A. reticulata and Diaphanoeca dilatanda. Two distinct clusters of species that are separated in time...

  8. Sea level anomaly in the North Atlantic and seas around Europe: Long-term variability and response to North Atlantic teleconnection patterns.

    Science.gov (United States)

    Iglesias, Isabel; Lorenzo, M Nieves; Lázaro, Clara; Fernandes, M Joana; Bastos, Luísa

    2017-12-31

    Sea level anomaly (SLA), provided globally by satellite altimetry, is considered a valuable proxy for detecting long-term changes of the global ocean, as well as short-term and annual variations. In this manuscript, monthly sea level anomaly grids for the period 1993-2013 are used to characterise the North Atlantic Ocean variability at inter-annual timescales and its response to the North Atlantic main patterns of atmospheric circulation variability (North Atlantic Oscillation, Eastern Atlantic, Eastern Atlantic/Western Russia, Scandinavian and Polar/Eurasia) and main driven factors as sea level pressure, sea surface temperature and wind fields. SLA variability and long-term trends are analysed for the North Atlantic Ocean and several sub-regions (North, Baltic and Mediterranean and Black seas, Bay of Biscay extended to the west coast of the Iberian Peninsula, and the northern North Atlantic Ocean), depicting the SLA fluctuations at basin and sub-basin scales, aiming at representing the regions of maximum sea level variability. A significant correlation between SLA and the different phases of the teleconnection patterns due to the generated winds, sea level pressure and sea surface temperature anomalies, with a strong variability on temporal and spatial scales, has been identified. Long-term analysis reveals the existence of non-stationary inter-annual SLA fluctuations in terms of the temporal scale. Spectral density analysis has shown the existence of long-period signals in the SLA inter-annual component, with periods of ~10, 5, 4 and 2years, depending on the analysed sub-region. Also, a non-uniform increase in sea level since 1993 is identified for all sub-regions, with trend values between 2.05mm/year, for the Bay of Biscay region, and 3.98mm/year for the Baltic Sea (no GIA correction considered). The obtained results demonstrated a strong link between the atmospheric patterns and SLA, as well as strong long-period fluctuations of this variable in spatial and

  9. Mitochondrial Ca2+ homeostasis during Ca2+ influx and Ca2+ release in gastric myocytes from Bufo marinus

    Science.gov (United States)

    Drummond, Robert M; Mix, T Christian H; Tuft, Richard A; Walsh, John V; Fay, Fredric S

    2000-01-01

    The Ca2+-sensitive fluorescent indicator rhod-2 was used to monitor mitochondrial Ca2+ concentration ([Ca2+]m) in gastric smooth muscle cells from Bufo marinus. In some studies, fura-2 was used in combination with rhod-2, allowing simultaneous measurement of cytoplasmic Ca2+ concentration ([Ca2+]i) and [Ca2+]m, respectively. During a short train of depolarizations, which causes Ca2+ influx from the extracellular medium, there was an increase in both [Ca2+]i and [Ca2+]m. The half-time (t½) to peak for the increase in [Ca2+]m was considerably longer than the t½ to peak for the increase in [Ca2+]i. [Ca2+]m remained elevated for tens of seconds after [Ca2+]i had returned to its resting value. Stimulation with caffeine, which causes release of Ca2+ from the sarcoplasmic reticulum (SR), also produced increases in both [Ca2+]i and [Ca2+]m. The values of t½ to peak for the increase in [Ca2+] in both cytoplasm and mitochondria were similar; however, [Ca2+]i returned to baseline values much faster than [Ca2+]m. Using a wide-field digital imaging microscope, changes in [Ca2+]m were monitored within individual mitochondria in situ, during stimulation of Ca2+ influx or Ca2+ release from the SR. Mitochondrial Ca2+ uptake during depolarizing stimulation caused depolarization of the mitochondrial membrane potential. The mitochondrial membrane potential recovered considerably faster than the recovery of [Ca2+]m. This study shows that Ca2+ influx from the extracellular medium and Ca2+ release from the SR are capable of increasing [Ca2+]m in smooth muscle cells. The efflux of Ca2+ from the mitochondria is a slow process and appears to be dependent upon the amount of Ca2+ in the SR. PMID:10713963

  10. Trans Atlantic Infrasound Payload (TAIP) Operation Plan.

    Energy Technology Data Exchange (ETDEWEB)

    Bowman, Daniel [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Lees, Jonathan M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2018-01-01

    The Carolina Infrasound package, added as a piggyback to the 2016 ULDB ight, recorded unique acoustic signals such as the ocean microbarom and a large meteor. These data both yielded unique insights into the acoustic energy transfer from the lower to the upper atmosphere as well as highlighted the vast array of signals whose origins remain unknown. Now, the opportunity to y a payload across the north Atlantic offers an opportunity to sample one of the most active ocean microbarom sources on Earth. Improvements in payload capabilities should result in characterization of the higher frequency range of the stratospheric infrasound spectrum as well. Finally, numerous large mining and munitions disposal explosions in the region may provide \\ground truth" events for assessing the detection capability of infrasound microphones in the stratosphere. The flight will include three different types of infrasound sensors. One type is a pair of polarity reversed InfraBSU microphones (standard for high altitude flights since 2016), another is a highly sensitive Chaparral 60 modified for a very low corner period, and the final sensor is a lightweight, low power Gem infrasound package. By evaluating these configurations against each other on the same flight, we will be able to optimize future campaigns with different sensitivity and mass constraints.

  11. Laser Ablation Trace Element Analysis of Modern and Fossil Desmophyllum dianthus from Norfolk and Baltimore Canyons in Mid-Atlantic Ocean

    Science.gov (United States)

    Schoemann, M.; Roark, B.; Fallon, S.; Eggins, S.; Kinsley, L.; Prouty, N.

    2015-12-01

    Deep-sea cup corals are a promising archive for paleoceanographic reconstructions as they are globally distributed with some fossil specimens living throughout the Holocene and into the Last Glacial period. Here we explore the utility of using laser ablation (LA)- ICP-MS to measure the trace elements and δ11B in solitary scleractinian, cup corals, Desmophyllum dianthus collected in Norfolk and Baltimore Canyons from the Mid-Atlantic Ocean. Twelve modern and twenty-six sub-fossil D. dianthus, were collected between a depth range of 400m - 1400m with ambient seawater pH range of 7.89 - 8.00. Modern seawater column chemistry including radiocarbon, nutrients, total alkalinity and particulate trace elements were measured to calibrate geochemical proxies in the live specimens. Radiocarbon measurements indicate sub-fossil specimens lived as long ago as 800 years. A suite of trace elements including P/Ca, Ba/Ca, and U/Ca were analyzed to reconstruct nutrient changes and carbonate ion concentrations. Using previously published calibration equations, modern coral P/Ca ratios yield dissolved inorganic P values of 0.24 - 1.70 μmol/L in line with measured values of 0.1-2.5 μmol/L in the water column. In addition, Ba/Ca (nutrients) yield dissolved Ba values of 25-137 ±16 nmol/kg and U/Ca results yield carbonate ion concentrations of 40-129 ±29 μmol/kg, which are both consistent with previously published work. This study represents the first ever LA-ICP-MS measurements of δ11B using modern and sub-fossil D. dianthus where the modern corals averaged δ11B=18.15±0.01‰. These results are similar to previously published solution ICP-MS results, but using published pH-δ11B calibration equation yields higher pH values than in-situ pH values suggesting future modern calibration work is necessary. Overall, these results show promise for using sub-fossil D. dianthus to reconstruct biogeochemical processes at intermediate and deep waters in Norfolk and Baltimore Canyons.

  12. Atlantic surfclam connectivity within the Middle Atlantic Bight: Mechanisms underlying variation in larval transport and settlement

    Science.gov (United States)

    Zhang, Xinzhong; Munroe, Daphne; Haidvogel, Dale; Powell, Eric N.

    2016-05-01

    Larval transport and settlement have been shown in various studies to be essential in determining population abundance and connectivity for benthic invertebrates. This transport is influenced by both the physical environment and biological behavior. The Atlantic surfclam, Spisula solidissima, is a commercially important benthic invertebrate fishery species along the U.S northeastern coast. In this study, a physical circulation model is coupled to a surfclam larval model to investigate the dynamics of larval transport and settlement within the Middle Atlantic Bight (MAB) shelf in 2006. The main physical mechanisms causing variability in larval transport and settlement are also examined. Model results show that surfclam larvae released from July to early October experience relatively larger settlement rates, due to higher average temperatures experienced by larvae. Larval along-shore transport exhibits a mean down-coast pattern following the coastal current from the northeast to the southwest, with most high-frequency (period of 2-10 days) variations caused by fluctuations in the along-shore surface wind stress, and with seasonal variations speculated to be driven mainly by changes in the across-shelf density gradient. Larval across-shelf movement is highly correlated with the along-shore surface wind stress mediated by coastal upwelling and downwelling episodes, but the correlation is further dependent on the vertical distribution of the larvae, particularly their position relative to the thermocline. Most surfclam larvae released from the Middle Atlantic shelf stay below the thermocline and experience a net onshore transport during the summer-stratified season when upwelling-favorable wind forcing dominates. A proposed critical value of water temperature at the thermocline successfully regulates the observed patterns of vertical distribution of surfclam larvae and their across-shelf movement off the New Jersey and South Virginia shelves; that is, when the water

  13. Ecosystem Alterations and Species Range Shifts: An Atlantic-Mediterranean Cephalaspidean Gastropod in an Inland Egyptian Lake.

    Science.gov (United States)

    Cruz-Rivera, Edwin; Malaquias, Manuel António E

    2016-01-01

    The eastern Atlantic and Mediterranean marine Cephalaspidea gastropod Haminoea orbignyana was collected from Lake Qarun (Fayoum, Egypt), a landlocked lake that has undergone a shift from freshwater to estuarine conditions in the past 100 years. Species identity was confirmed by both morphological (anatomical dissection and scanning electron microscopy) and molecular methods (COI gene phylogeny). Observations suggested a robust population of H. orbignyana in the lake with a density of ca. 64 individuals/m2 and ca. 105 egg masses/m2 during surveys conducted in the summer of 2013. The vast majority of snails and egg masses were found under rocks. Observations of egg masses in the lab showed a gradual change from whitish to yellow-green as the eggs matured and the release of veliger larvae alone after about a week. Although adult cephalaspideans readily consumed filamentous red and green algae, and cyanobacteria, laboratory trials showed that they consumed significantly more of the red alga Ceramium sp., than of the green alga Cladophora glomerata, with consumption of Oscillatoria margaritifera being similar to those on the two algae. When grown on these resources for 16 days, H. orbignyana maintained their mass on the rhodophyte and cyanobacterium, but not in starvation controls. No cephalaspideans grew over the course of this experiment. Lake Qarun has been periodically restocked with Mediterranean fishes and prawns since the 1920s to maintain local fisheries, which represents a possible route of colonization for H. orbignyana. Yet, based on literature records, it seems more likely that invasion of the lake by this gastropod species has occurred only within the last 20 years. As human activities redistribute species through direct and indirect means, the structure of the community of this inland lake has become unpredictable and the long-term effects of these recent introductions are unknown.

  14. Ecosystem Alterations and Species Range Shifts: An Atlantic-Mediterranean Cephalaspidean Gastropod in an Inland Egyptian Lake.

    Directory of Open Access Journals (Sweden)

    Edwin Cruz-Rivera

    Full Text Available The eastern Atlantic and Mediterranean marine Cephalaspidea gastropod Haminoea orbignyana was collected from Lake Qarun (Fayoum, Egypt, a landlocked lake that has undergone a shift from freshwater to estuarine conditions in the past 100 years. Species identity was confirmed by both morphological (anatomical dissection and scanning electron microscopy and molecular methods (COI gene phylogeny. Observations suggested a robust population of H. orbignyana in the lake with a density of ca. 64 individuals/m2 and ca. 105 egg masses/m2 during surveys conducted in the summer of 2013. The vast majority of snails and egg masses were found under rocks. Observations of egg masses in the lab showed a gradual change from whitish to yellow-green as the eggs matured and the release of veliger larvae alone after about a week. Although adult cephalaspideans readily consumed filamentous red and green algae, and cyanobacteria, laboratory trials showed that they consumed significantly more of the red alga Ceramium sp., than of the green alga Cladophora glomerata, with consumption of Oscillatoria margaritifera being similar to those on the two algae. When grown on these resources for 16 days, H. orbignyana maintained their mass on the rhodophyte and cyanobacterium, but not in starvation controls. No cephalaspideans grew over the course of this experiment. Lake Qarun has been periodically restocked with Mediterranean fishes and prawns since the 1920s to maintain local fisheries, which represents a possible route of colonization for H. orbignyana. Yet, based on literature records, it seems more likely that invasion of the lake by this gastropod species has occurred only within the last 20 years. As human activities redistribute species through direct and indirect means, the structure of the community of this inland lake has become unpredictable and the long-term effects of these recent introductions are unknown.

  15. 75 FR 35435 - Fisheries of the Northeastern United States; Atlantic Deep-Sea Red Crab Fisheries; 2010 Atlantic...

    Science.gov (United States)

    2010-06-22

    ... United States; Atlantic Deep-Sea Red Crab Fisheries; 2010 Atlantic Deep-Sea Red Crab Specifications In... finalized 2010 specifications for the Atlantic deep-sea red crab fishery, including a target total allowable... Atlantic Deep-Sea Red Crab Fishery Management Plan (FMP) allow NMFS to make an in-season adjustment to the...

  16. 75 FR 49420 - Fisheries of the Northeastern United States; Atlantic Deep-Sea Red Crab Fisheries; 2010 Atlantic...

    Science.gov (United States)

    2010-08-13

    ... United States; Atlantic Deep-Sea Red Crab Fisheries; 2010 Atlantic Deep-Sea Red Crab Specifications In... (TAC) and corresponding fleet days-at-sea (DAS) allocation for the Atlantic deep- sea red crab fishery... the implementing regulations for the Atlantic Deep- Sea Red Crab Fishery Management Plan (FMP...

  17. 75 FR 7435 - Fisheries of the Northeastern United States; Atlantic Deep-Sea Red Crab Fisheries; 2010 Atlantic...

    Science.gov (United States)

    2010-02-19

    ... United States; Atlantic Deep-Sea Red Crab Fisheries; 2010 Atlantic Deep-Sea Red Crab Specifications... Atlantic deep-sea red crab fishery, including a target total allowable catch (TAC) and a fleet-wide days-at-sea (DAS) allocation. The implementing regulations for the Atlantic Deep-Sea Red Crab Fishery...

  18. Two phases of the Holocene East African Humid Period: Inferred from a high-resolution geochemical record off Tanzania

    Science.gov (United States)

    Liu, Xiting; Rendle-Bühring, Rebecca; Kuhlmann, Holger; Li, Anchun

    2017-02-01

    During the Holocene, the most notably climatic change across the African continent is the African Humid Period (AHP), however the pace and primary forcing for this pluvial condition is still ambiguous, particularly in East Africa. We present a high-resolution marine sediment record off Tanzania to provide insights into the climatic conditions of inland East Africa during the Holocene. Major element ratios (i.e., log-ratios of Fe/Ca and Ti/Ca), derived from X-Ray Fluorescence scanning, have been employed to document variations in humidity in East Africa. Our results show that the AHP is represented by two humid phases: an intense humid period from the beginning of the Holocene to 8 ka (AHP I); and a moderate humid period spanning from 8 to 5.5 ka (AHP II). On the basis of our geochemical record and regime detection, the termination of the AHP initiated at 5.5 ka and ceased around 3.5 ka. Combined with other paleoclimatic records around East Africa, we suggest that the humid conditions in this region responded to Northern Hemisphere (NH) summer insolation. The AHP I and II might have been related to an eastward shift of the Congo Air Boundary and warmer conditions in the western Indian Ocean, which resulted in additional moisture being delivered from the Atlantic and Indian Oceans during the NH summer and autumn, respectively. We further note a drought event throughout East Africa north of 10°S around 8.2 ka, which may have been related to the southward migration of the Intertropical Convergence Zone in response to the NH cooling event.

  19. Transition from the Cretaceous ocean to Cenozoic circulation in the western South Atlantic - A twofold reconstruction

    Science.gov (United States)

    Uenzelmann-Neben, Gabriele; Weber, Tobias; Grützner, Jens; Thomas, Maik

    2017-10-01

    The Cretaceous oceanic circulation has been quite different from the modern with a different distribution of the continents on the globe. This has resulted in a much lower temperature gradient between poles and equator. We have studied seismic reflection data and used numerical simulations of atmosphere and ocean dynamics to identify important steps in modifications of the oceanic circulation in the South Atlantic from the Cretaceous to the Cenozoic and the major factors controlling them. Starting in the Albian we could not identify any traces of an overturning circulation for the South Atlantic although a weak proto-Antarctic Circumpolar Current (ACC) was simulated. No change in circulation was observed for the Paleocene/early Eocene South Atlantic, which indicated that this period has witnessed a circulation similar to the Albian and Cenomanian/Turonian circulation. The most drastic modifications were observed for the Eocene/Oligocene boundary and the Oligocene/early Miocene with the onset of an ACC and Atlantic meridional overturning circulation (AMOC) and hence southern sourced deep and bottom water masses in the western South Atlantic. A modern AMOC, which intensified in strength after closure of the Central American Seaway (CAS), and a strong ACC have resulted in current controlled sedimentary features and wide spread hiatusses in the South Atlantic since the middle Miocene. The opening of Drake Passage in early Oligocene times and the closure of the CAS at 6 Ma, i.e., tectonic processes, have been identified as the key triggers for the observed most severe changes in oceanic circulation in the South Atlantic.

  20. Habitat selection and overlap of Atlantic salmon and smallmouth bass juveniles in nursery streams

    Science.gov (United States)

    Wathen, G.; Coghlan, S.M.; Zydlewski, Joseph D.; Trial, J.G.

    2011-01-01

    Introduced smallmouth bass Micropterus dolomieu have invaded much of the historic freshwater habitat of Atlantic salmon Salmo salar in North America, yet little is known about the ecological interactions between the two species. We investigated the possibility of competition for habitat between age-0 Atlantic salmon and age-0 and age-1 smallmouth bass by means of in situ observations and a mesocosm experiment. We used snorkel observation to identify the degree and timing of overlap in habitat use in our in situ observations and to describe habitat shifts by Atlantic salmon in the presence of smallmouth bass in our mesocosm experiments. In late July 2008, we observed substantial overlap in the depths and mean water column velocities used by both species in sympatric in situ conditions and an apparent shift by age-0 Atlantic salmon to shallower water that coincided with the period of high overlap. In the mesocosm experiments, we detected no overlap or habitat shifts by age-0 Atlantic salmon in the presence age-1 smallmouth bass and low overlap and no habitat shifts of Atlantic salmon and age-0 smallmouth bass in fall 2009. In 2009, summer floods with sustained high flows and low temperatures resulted in the nearly complete reproductive failure of the smallmouth bass in our study streams, and we did not observe a midsummer habitat shift by Atlantic salmon similar to that seen in 2008. Although this prevented us from replicating our 2008 experiments under similar conditions, the virtual year-class failure of smallmouth bass itself is enlightening. We suggest that future studies incorporate the effects of varying temperature and discharge to determine how abiotic factors affect the interactions between these species and thus mediate the outcomes of potential competition.

  1. CaMELS: In silico prediction of calmodulin binding proteins and their binding sites.

    Science.gov (United States)

    Abbasi, Wajid Arshad; Asif, Amina; Andleeb, Saiqa; Minhas, Fayyaz Ul Amir Afsar

    2017-09-01

    Due to Ca 2+ -dependent binding and the sequence diversity of Calmodulin (CaM) binding proteins, identifying CaM interactions and binding sites in the wet-lab is tedious and costly. Therefore, computational methods for this purpose are crucial to the design of such wet-lab experiments. We present an algorithm suite called CaMELS (CalModulin intEraction Learning System) for predicting proteins that interact with CaM as well as their binding sites using sequence information alone. CaMELS offers state of the art accuracy for both CaM interaction and binding site prediction and can aid biologists in studying CaM binding proteins. For CaM interaction prediction, CaMELS uses protein sequence features coupled with a large-margin classifier. CaMELS models the binding site prediction problem using multiple instance machine learning with a custom optimization algorithm which allows more effective learning over imprecisely annotated CaM-binding sites during training. CaMELS has been extensively benchmarked using a variety of data sets, mutagenic studies, proteome-wide Gene Ontology enrichment analyses and protein structures. Our experiments indicate that CaMELS outperforms simple motif-based search and other existing methods for interaction and binding site prediction. We have also found that the whole sequence of a protein, rather than just its binding site, is important for predicting its interaction with CaM. Using the machine learning model in CaMELS, we have identified important features of protein sequences for CaM interaction prediction as well as characteristic amino acid sub-sequences and their relative position for identifying CaM binding sites. Python code for training and evaluating CaMELS together with a webserver implementation is available at the URL: http://faculty.pieas.edu.pk/fayyaz/software.html#camels. © 2017 Wiley Periodicals, Inc.

  2. Homing Behaviour in an Atlantic Walrus (Odobenus rosmarus rosmarus)

    DEFF Research Database (Denmark)

    Born, Erik W.; Aquarone, Mario; Knutsen, Lars Ø.

    2005-01-01

    four inshore summering periods (August to September), the animal used only one terrestrial haul-out from which it made excursions to the same general shallow water area (i.e., likely clam beds) in western Dove Bay (ca. 76º to 77º N). In different years, the size of the inshore foraging area varied...

  3. Plio-Pleistocene records from the South East Atlantic reveal changes in the Agulhas leakage

    Science.gov (United States)

    Dekens, P. S.; Kynett, K.; Wojcieszek, D. E.

    2012-12-01

    The early Pliocene (3.5 to 5 Ma) is the most recent time in Earth's history when global climate was significantly warmer than today. Although atmospheric pCO2 (360-410 ppm) was similar to today, average global temperature was 3-4°C warmer, ice sheets were smaller, and sea level was ~35 m higher than today. Zonal and meridional sea surface temperature (SST) gradients were reduced in the early Pliocene, Walker circulation was weaker, and Hadley circulation was weaker and expanded poleward. Changes in shallow overturning circulation (the ventilated thermocline) and ocean heat transport may have played a role in the Plio-Pleistocene climate transition. However, most early Pliocene SST records are in the northern hemisphere, the tropics, and coastal upwelling regions, while data from the subtropical southern hemisphere is scarce. We present Mg/Ca and δ 18 O records from 4 species of planktonic foraminifera (G. ruber , G. sacculifer , G. tumida , and G. crassiformis ) from ODP site 1264 (28.53°S; 2.85°E, 2505 m water depth) located on the Walvis Ridge in the southeastern Atlantic. Combined Mg/Ca and δ 18 O measurements on species with different depth habitats allow us to reconstruct changes in temperature and salinity in the upper water column. The Mg/Ca record of G. sacculifer , a surface dwelling species, shows no long-term trend in SST over the past 4 Ma while the δ 18 O record indicates sea surface salinity gradually decreased from the early Pliocene to today. Mg/Ca and δ 18 O of subsurface species show a similar pattern: no long-term trend in temperature, but a marked freshening from the early Pliocene to today Increased salinity in both the surface and subsurface could be due to increased Agulhas leakage (AL), which delivers relatively salty water to the region. The strength of AL is controlled by the position of the sub-tropical front; a southward shift of the front widens the Agulhas corridor and allows increased AL. A sub-Antarctic SST record displays ~4

  4. Neotectonism along the Atlantic passive continental margin: A review

    Science.gov (United States)

    Gardner, Thomas W.

    1989-09-01

    An extensive body of geologic data including the modern state of stress, historical seismicity, surface and subsurface stratigraphy, numerical models of crustal deformation, surficial geomorphic systems, and historical precise leveling and tidal gauge records constrain the style and rate of neotectonic deformation for the Appalachians and Atlantic passive continental margin. There are two major styles of neotectonism in the eastern United States. The northeastern United States is dominated by isostatic uplift and northward migration of peripheral bulge collapse in response to deglaciation. This locally rapid, but decreasing rate of deformation is superimposed upon slower, long-term deformation along the Atlantic margin. Most of the long-term, continental margin deformation is attributed to lithospheric flexuring in response to sediment loading in sedimentary basins (especially the Baltimore Canyon Trough and Carolina Trough), isostatic deformation in response to continental denudation and water loading of the shelf, and stress from far-field plate tectonic sources. Significant deformational features include an uplift anomaly near Cape Fear, N.C.; northward and southward tilting of the Coastal Plain into the Salisbury and Southeast Georgia Embayments respectively; seaward tilting of the Coastal Plain/Piedmont, and a complex pattern of postglacial uplift and later subsidence in the northeast. Estimates of vertical crustal velocities for similar locations vary over several orders of magnitude. Measurement interval bias and systematic leveling errors may account for some of the discrepancies. Evidence for periodic deformation in the eastern United States in substantial and it is possible that historic data indicate a period of accelerated deformation along the Atlantic continental margin.

  5. ANALYSIS OF THE APPROACH TO THE ATLANTIC FOREST IN HIGH SCHOOL BIOLOGY TEXTBOOKS

    Directory of Open Access Journals (Sweden)

    Nicácio Oliveira Freitas

    2017-03-01

    Full Text Available The textbooks are the main teaching tool for students and teachers. The analysis of these books enables point out several shortcomings in relation to the contents approach. Thus, the objective of this work was to analyze the approach to the Atlantic Forest, considered one of the most degraded environments of the world. A total of seven high school biology textbooks were analyzed, following an evaluation script with general information, biotic and abiotic factors, environmental conservation and anthropic action, which were considered as satisfactory or unsatisfactory in the textbooks evaluation. In general, the Atlantic Forest theme has been addressed by all assessed books, including specific topics, however, some aspects such as the use of images was made improperly, leading to misunderstandings about Atlantic forest. In addition, ecosystem dynamics, its components and the environmental impacts have not been addressed satisfactorily in the majority of the works assessed. In general, the theme Atlantic Forest has been addressed by all assessed books, including specific topics, however, many aspects of this theme presented problems in their approach: update, concepts, definitions and importance, and also presented problems in their illustration of the current situation of Atlantic Forest. Periodic revisions of these textbooks are of great importance to assure student formation that allows them to analyze and know the effects of their actions on the environment and to reflect on ways to alleviates them. Keywords: biology textbooks; ecosystem; contents analysis.

  6. Mechanics of Old Faithful Geyser, Calistoga, CA

    Science.gov (United States)

    Rudolph, M.L.; Manga, M.; Hurwitz, Shaul; Johnston, Malcolm J.; Karlstrom, L.; Wang, Chun-Yong

    2012-01-01

    In order to probe the subsurface dynamics associated with geyser eruptions, we measured ground deformation at Old Faithful Geyser of Calistoga, CA. We present a physical model in which recharge during the period preceding an eruption is driven by pressure differences relative to the aquifer supplying the geyser. The model predicts that pressure and ground deformation are characterized by an exponential function of time, consistent with our observations. The geyser's conduit is connected to a reservoir at a depth of at least 42 m, and pressure changes in the reservoir can produce the observed ground deformations through either a poroelastic or elastic mechanical model.

  7. Possible involvement of transient receptor potential ankyrin 1 in Ca2+signaling via T-type Ca2+channel in mouse sensory neurons.

    Science.gov (United States)

    Nishizawa, Yuki; Takahashi, Kenji; Oguma, Naoko; Tominaga, Makoto; Ohta, Toshio

    2017-12-28

    T-type Ca 2+ channels and TRPA1 are expressed in sensory neurons and both are associated with pain transmission, but their functional interaction is unclear. Here we demonstrate that pharmacological evidence of the functional relation between T-type Ca 2+ channels and TRPA1 in mouse sensory neurons. Low concentration of KCl at 15 mM (15K) evoked increases of intracellular Ca 2+ concentration ([Ca 2+ ] i ), which were suppressed by selective T-type Ca 2+ channel blockers. RT-PCR showed that mouse sensory neurons expressed all subtypes of T-type Ca 2+ channel. The magnitude of 15K-induced [Ca 2+ ] i increase was significantly larger in neurons sensitive to allylisothiocyanate (AITC, a TRPA1 agonist) than in those insensitive to it, and in TRPA1 -/- mouse sensory neurons. TRPA1 blockers diminished the [Ca 2+ ] i responses to 15K in neurons sensitive to AITC, but failed to inhibit 40 mM KCl-induced [Ca 2+ ] i increases even in AITC-sensitive neurons. TRPV1 blockers did not inhibit the 15K-induced [Ca 2+ ] i increase regardless of the sensitivity to capsaicin. [Ca 2+ ] i responses to TRPA1 agonist were enhanced by co-application with 15K. These pharmacological data suggest the possibility of functional interaction between T-type Ca 2+ channels and TRPA1 in sensory neurons. Since TRPA1 channel is activated by intracellular Ca 2+ , we hypothesize that Ca 2+ entered via T-type Ca 2+ channel activation may further stimulate TRPA1, resulting in an enhancement of nociceptive signaling. Thus, T-type Ca 2+ channel may be a potential target for TRPA1-related pain. © 2017 Wiley Periodicals, Inc.

  8. Environmental Assessment for Atlantic White Cedar Restoration Project at Dare County Range, Seymour Johnson Air Force Base, North Carolina

    Science.gov (United States)

    2014-12-23

    int o this ca lculato r. ot be us ed fo r e mission inve ntory or fo rma l carbon footprinting exercises. Read more a bout the cav eats and expla n...Atlantic white cedar seedlings are established, wetland-approved herbicides would be used to control competing vegetation if seedling survival was at...would be expected to have only negligible, if any, impacts to floodplains. Biological Resources Vegetation : Implementing the Preferred Alternative

  9. Northwest Atlantic Regional Climatology (NCEI Accession 0155889)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — To provide an improved oceanographic foundation and reference for multi-disciplinary studies of the Northwest Atlantic Ocean, NCEI Regional Climatology Team...

  10. Mountain ranges favour vigorous Atlantic meridional overturning

    National Research Council Canada - National Science Library

    Bablu Sinha; Adam T. Blaker; Joël J.-M. Hirschi; Sarah Bonham; Matthew Brand; Simon Josey; Robin S. Smith; Jochem Marotzke

    2012-01-01

      We use a global Ocean-Atmosphere General Circulation Model (OAGCM) to show that the major mountain ranges of the world have a significant role in maintenance of the Atlantic Meridional Overturning Circulation (AMOC...

  11. Atlantic Surfclam and Ocean Quahog Survey

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The standardized NEFSC Atlantic Surfclam and Ocean Quahog Survey has covered an area from Cape Hatteras to Georges Bank. The survey was conducted every two or three...

  12. Atlantic energy and the strategic outlook

    Directory of Open Access Journals (Sweden)

    Paul Isbell

    2013-09-01

    Full Text Available Sweeping changes are beginning to transform energy scenarios around the world. The gas revolution, a renaissance in petroleum technology and exploration, and a chaotic but powerful movement toward the goal of low-carbon economies are three of the principal energy trends currently interacting with structural changes in the geo-economics of the Atlantic world to present new perspectives and opportunitiesfor the diverse actors in the ‘Atlantic Basin’. This article explores how changes in the energy landscape are contributing to a reassessment of the strategic horizon. The potential impacts of the shale revolution, deep-offshore oil, biofuels and other modern renewable energies on the geopolitics of the Atlantic Basin will be assessed, and the hypothesis that an Atlantic Basin energy system is now taking shape will be evaluated, along with an analysis of anticipated impacts.

  13. Atlantic NAD 83 Continental Shelf Boundary (CSB)

    Data.gov (United States)

    Bureau of Ocean Energy Management, Department of the Interior — This data set contains Continental Shelf Boundary (CSB) lines in ESRI shapefile format for the BOEM Atlantic Region. The CSB defines the seaward limit of federally...

  14. Atlantic Marine Mammal Assessment Vessel Surveys

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data sets are a compilation of large vessel surveys for marine mammal stock assessments in South Atlantic (Florida to Maryland) waters from 1994 to the...

  15. Atlantic Sharpnose Shark Reproductive Biology Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Reproductive data from Atlantic sharpnose sharks were collected from specimens captured throughout the northern Gulf of Mexico on various research vessels. Data...

  16. Atlantic-THORpex Observing System Test

    Data.gov (United States)

    National Aeronautics and Space Administration — Atlantic - THORpex Observing System Test (ATOST) is part of an international research program to accelerate improvements in the accuracy of 1 to 14 day weather...

  17. Atlantic NAD 83 SLA Baseline Points

    Data.gov (United States)

    Bureau of Ocean Energy Management, Department of the Interior — This data set contains baseline points in ArcGIS shapefile format for the BOEM Atlantic Region. Baseline points are the discrete coordinate points along the...

  18. Atlantic NAD 83 SLA Baseline Tangents

    Data.gov (United States)

    Bureau of Ocean Energy Management, Department of the Interior — This data set contains baseline tangent lines in ArcGIS shapefile format for the BOEM Atlantic Region. Baseline tangent lines are typically bay or river closing...

  19. Are Postgraduate Medical Residency Training Positions in Atlantic Canada Evenly Distributed?

    Science.gov (United States)

    Atkinson, Paul; Howlett, Mike; MacKay, Jacqueline; Fraser, Jacqueline; Ross, Peter

    2016-04-17

    Background The distribution of postgraduate medical training (residency) positions in Canada is administered by medical schools and universities in conjunction with individual provinces. In Atlantic Canada, the Maritime provinces are considered a single unit under Dalhousie University in Nova Scotia (NS), although distributed medical undergraduate education through Dalhousie and Sherbrooke has enabled medical students to complete their entire course of study in New Brunswick (NB). It is unclear if postgraduate medical education has been distributed in a similar fashion in Atlantic Canada, particularly in New Brunswick and Prince Edward Island (PE). Methods Data on the number of R1 residency positions was obtained from the Canadian Resident Matching Service (CaRMS) database. The distribution of R1 positions was described and compared nationally and through the Atlantic provinces. The analysis was completed using MS Excel and Prism. Results Rates of R1 positions per million persons varied widely; the national median rate was 97 positions per million persons, with a range of 34 to 138. The combined Maritime provinces rate of R1 positions was 71 per million persons and the rate in Newfoundland (NL) was 138 positions per million. The NS rate was 106 positions per million while the NB rate was 54 per million and the PE rate 34 per million. Sixty-four percent of all residency training positions in Atlantic Canada were based in the two most urban areas of Halifax, NS or St John's, NL. Royal College (specialty) positions were more likely to be based at the main university campus city than family medicine training positions (97 vs. 3%; 33 vs. 67%, respectively). Conclusion There is a high level of variation in available residency positions among the individual provinces, especially in Atlantic Canada. The lower prevalence of opportunities in NB and PE may influence the ability of these provinces to recruit and retain new physicians.

  20. Coccolithophore ecology in the tropical and subtropical Atlantic Ocean: New perspectives from the Atlantic meridional transect (AMT) programme

    Science.gov (United States)

    Poulton, Alex J.; Holligan, Patrick M.; Charalampopoulou, Anastasia; Adey, Tim R.

    2017-11-01

    Coccolithophore species composition was determined in 199 samples collected from the upper 300 m of the Atlantic Ocean, spanning temperate, tropical and subtropical waters in both hemispheres during four Atlantic Meridional Transect (AMT) cruises over the period 2003-2005. Of the 171 taxa observed, 140 consistently represented 10% surface irradiance); the lower euphotic zone (LEZ, 10-1% surface irradiance); and the sub-euphotic zone (SEZ, strategy for species abundant (Umbellosphaera spp., holococcolithophores) in the UEZ where inorganic nutrient concentrations are depleted and limiting to growth, although other nutritional strategies, such as the use of organic nutrients, are also possible. Statistical differences were also found in the species composition between the different cruises, with high levels of similarity for similar timed cruises (May or September-October). Few individual taxa showed significant variability in abundance over the time-span of sampling, except species such as E. huxleyi and G. ericsonii at higher latitudes. In subtropical and equatorial waters, high levels of species richness and low levels of species dominance remained throughout the sampling period indicating that seasonal fluctuations reflected differences in the whole coccolithophore community rather than in just one or a few species. Multivariate analyses of the taxa classified as rare also indicated some level of temporal, as well as vertical, zonation. Such insights into coccolithophore ecology and community composition provide important new perspectives that require innovative research to fully understand their impact on ocean biogeochemistry.

  1. Initializing decadal climate predictions over the North Atlantic region

    Science.gov (United States)

    Matei, Daniela Mihaela; Pohlmann, Holger; Jungclaus, Johann; Müller, Wolfgang; Haak, Helmuth; Marotzke, Jochem

    2010-05-01

    Decadal climate prediction aims to predict the internally-generated decadal climate variability in addition to externally-forced climate change signal. In order to achieve this it is necessary to start the predictions from the current climate state. In this study we investigate the forecast skill of the North Atlantic decadal climate predictions using two different ocean initialization strategies. First we apply an assimilation of ocean synthesis data provided by the GECCO project (Köhl and Stammer, 2008) as initial conditions for the coupled model ECHAM5/MPI-OM. Hindcast experiments are then performed over the period 1952-2001. An alternative approach is one in which the subsurface ocean temperature and salinity are diagnosed from an ensemble of ocean model runs forced by the NCEP-NCAR atmospheric reanalyzes for the period 1948-2007, then nudge into the coupled model to produce initial conditions for the hindcast experiments. An anomaly coupling scheme is used in both approaches to avoid the hindcast drift and the associated initial shock. Differences between the two assimilation approaches are discussed by comparing them with the observational data in key regions and processes. We asses the skill of the initialized decadal hindcast experiments against the prediction skill of the non-initialized hindcasts simulation. We obtain an overview of the regions with the highest predictability from the regional distribution of the anomaly correlation coefficients and RMSE for the SAT. For the first year the hindcast skill is increased over almost all ocean regions in the NCEP-forced approach. This increase in the hindcast skill for the 1 year lead time is somewhat reduced in the GECCO approach. At lead time 5yr and 10yr, the skill enhancement is still found over the North Atlantic and North Pacific regions. We also consider the potential predictability of the Atlantic Meridional Overturning Circulation (AMOC) and Nordic Seas Overflow by comparing the predicted values to

  2. Property Changes of Abyssal Waters in the Western Tropical Atlantic

    Science.gov (United States)

    Herrford, Josefine; Brandt, Peter; Zenk, Walter

    2017-04-01

    Flowing northward towards the equator, Antarctic Bottom Water (AABW) encounters the lighter overlying North Atlantic Deep Water (NADW), both water masses creating an abyssal stratification and gradually mixing across their interface. Changes in the associated water mass formation and/or along-path transformation, observable in the evolution of water mass volume and characteristics, might impact the deep oceans uptake of anthropogenic CO2 or its contribution to global sea level rise. We compile historic and recent shipboard measurements of hydrography and velocity to provide a comprehensive view on water mass distribution, pathways, along-path transformation and long-term temperature changes of abyssal waters in the western South and Equatorial Atlantic. We are able to confirm previous results showing that the northwest corner of the Brazil Basin represents a splitting point for the southward/northward flow of NADW/AABW. The available measurements sample water mass transformation along the two major routes for deep and bottom waters in the tropical to South Atlantic - along the deep western boundary and eastward, parallel to the equator - as well as the hot spots of extensive mixing. We find lower NADW and lighter AABW to form a highly interactive transition layer in the northern Brazil Basin. The AABW north of 5°S is relatively homogeneous with only lighter AABW being able to pass through the Equatorial Channel (EQCH) into the North Atlantic. Spanning a period of 26 years, our data also allow an estimation of long-term temperature trends in abyssal waters. We find a warming of 2.5 ± 0.7•10-3 °C yr-1 of the waters in the northern Brazil Basin being colder than 0.6 °C throughout the period 1989-2014 and can relate that warming to a thinning of the dense AABW layer. While isopycnal heave is the dominant effect defining the vertical distribution of temperature trends on isobars, we also find temperature changes on isopycnals in the transition layer the lower NADW

  3. CA125 in ovarian cancer

    DEFF Research Database (Denmark)

    Duffy, M J; Bonfrer, J M; Kulpa, J

    2005-01-01

    CA125 is currently the most widely used tumor marker for ovarian epithelial cancer. The aim of this article is to provide guidelines for the routine clinical use of CA125 in patients with ovarian cancer. Due to lack of sensitivity for stage I disease and lack of specificity, CA125 is of little...... value in the detection of early ovarian cancer. At present, therefore, CA125, either alone or in combination with other modalities, cannot be recommended for screening for ovarian cancer in asymptomatic women outside the context of a randomized controlled trial. Preoperative levels in postmenopausal...... women, however, may aid the differentiation of benign and malignant pelvic masses. Serial levels during chemotherapy for ovarian cancer are useful for assessing response to treatment. Although serial monitoring following initial chemotherapy can lead to the early detection of recurrent disease...

  4. Sonoma County, CA, 2013 Lidar

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Sonoma County Vegetation Mapping and LiDAR Consortium retained WSI to provide lidar and Orthophoto data and derived products in Sonoma County, CA. A classified LAS...

  5. Millennial-scale variations in dustiness recorded in Mid-Atlantic sediments from 0 to 70 ka

    Science.gov (United States)

    Middleton, Jennifer L.; Mukhopadhyay, Sujoy; Langmuir, Charles H.; McManus, Jerry F.; Huybers, Peter J.

    2018-01-01

    Sedimentary records of dust deposition in the subtropical Atlantic provide important constraints on millennial- and orbital-scale variability in atmospheric circulation and North African aridity. Constant flux proxies, such as extraterrestrial helium-3, yield dust flux records that are independent of the biases caused by lateral sediment transport and limited resolution that may be associated with age-model-derived mass accumulation rates. However, Atlantic dust records constrained using constant flux proxies are sparsely distributed and generally limited to the past 20 ka. Here we extend the Atlantic record of North African dust deposition to 70 ka using extraterrestrial helium-3 and measurements of titanium, thorium, and terrigenous helium-4 in two sediment cores collected at 26°N and 29°N on the Mid-Atlantic Ridge and compare results to model estimates for dust deposition in the subtropical North Atlantic. Dust proxy fluxes between 26°N and 29°N are well correlated, despite variability in lateral sediment transport, and underscore the utility of extraterrestrial helium-3 for constraining millennial-scale variability in dust deposition. Similarities between Mid-Atlantic dust flux trends and those observed along the Northwest African margin corroborate previous interpretations of dust flux variability over the past 20 ka and suggest that long distance transport and depositional processes do not overly obscure the signal of North African dust emissions. The 70 ka Mid-Atlantic record reveals a slight increase in North African dustiness from Marine Isotope Stage 4 through the Last Glacial Maximum and a dramatic decrease in dustiness associated with the African Humid Period. On the millennial-scale, the new records exhibit brief dust maxima coincident with North Atlantic cold periods such as the Younger Dryas, and multiple Heinrich Stadials. The correlation between Mid-Atlantic dust fluxes and previous constraints on North African aridity is high. However

  6. 75 FR 57698 - Atlantic Highly Migratory Species; Atlantic Billfish Management, White Marlin (Kajikia albidus

    Science.gov (United States)

    2010-09-22

    ... marlin as the waters of the entire Atlantic Ocean and maintained the management unit definitions of... the HMS definition in the MSA, when the Regional Fishery Management Councils managed Atlantic HMS, the... definition and to continue to manage that species via Secretarial management. This action will amend the MSA...

  7. 76 FR 65700 - Atlantic Highly Migratory Species; Advisory Panel for Atlantic Highly Migratory Species Southeast...

    Science.gov (United States)

    2011-10-24

    ... National Oceanic and Atmospheric Administration RIN 0648-XA776 Atlantic Highly Migratory Species; Advisory Panel for Atlantic Highly Migratory Species Southeast Data, Assessment, and Review Workshops AGENCY... Migratory Species (HMS) Southeast Data, Assessment, and Review (SEDAR) Workshops (this AP is also called the...

  8. Response of the Atlantic overturning circulation to South Atlantic sources of buoyancy

    NARCIS (Netherlands)

    Weijer, W.; Ruijter, W.P.M. de; Sterl, A.; Drijfhout, S.

    2001-01-01

    The heat and salt input from the Indian to Atlantic Oceans by Agulhas Leakage is found to influence the Atlantic overturning circulation in a low-resolution Ocean General Circulation Model. The model used is the Hamburg Large-Scale Geostrophic (LSG) model, which is forced by mixed boundary

  9. 75 FR 30483 - Atlantic Highly Migratory Species; Atlantic Shark Management Measures; Amendment 3

    Science.gov (United States)

    2010-06-01

    ... Species; Atlantic Shark Management Measures; Amendment 3; Final Rule #0;#0;Federal Register / Vol. 75 , No... Species; Atlantic Shark Management Measures; Amendment 3 AGENCY: National Marine Fisheries Service (NMFS... management alternatives available to rebuild blacknose sharks and end overfishing of blacknose and shortfin...

  10. 77 FR 35357 - Atlantic Highly Migratory Species; Commercial Atlantic Region Non-Sandbar Large Coastal Shark...

    Science.gov (United States)

    2012-06-13

    ...; Commercial Atlantic Region Non-Sandbar Large Coastal Shark Fishery Opening Date AGENCY: National Marine...-sandbar large coastal shark fishery. This action is necessary to inform fishermen and dealers about the fishery opening date. DATES: The commercial Atlantic region non-sandbar large coastal shark fishery will...

  11. 75 FR 22103 - Atlantic Coastal Fisheries Cooperative Management Act Provisions; Atlantic Coastal Shark Fishery

    Science.gov (United States)

    2010-04-27

    ... Management Act Provisions; Atlantic Coastal Shark Fishery AGENCY: National Marine Fisheries Service (NMFS... Atlantic Coastal Sharks (Plan) and that the measures New Jersey has failed to implement and enforce are necessary for the conservation of the shark resource. This determination is consistent with the findings of...

  12. 75 FR 57235 - Atlantic Highly Migratory Species; Atlantic Shark Management Measures

    Science.gov (United States)

    2010-09-20

    ... Species; Atlantic Shark Management Measures AGENCY: National Marine Fisheries Service (NMFS), National....S. Atlantic shark fishery to address several specific issues currently affecting management of the shark fishery and to identify specific goals for management of fishery in the future. NMFS is requesting...

  13. 78 FR 70500 - Atlantic Highly Migratory Species; 2014 Atlantic Shark Commercial Fishing Seasons

    Science.gov (United States)

    2013-11-26

    ...; 2014 Atlantic Shark Commercial Fishing Seasons AGENCY: National Marine Fisheries Service (NMFS... for the Atlantic commercial shark fisheries. The quota adjustments are based on over- and/or... for commercial shark fishermen in all regions and areas. These actions could affect fishing...

  14. 77 FR 75896 - Atlantic Highly Migratory Species; 2013 Atlantic Shark Commercial Fishing Season

    Science.gov (United States)

    2012-12-26

    ... Species; 2013 Atlantic Shark Commercial Fishing Season AGENCY: National Marine Fisheries Service (NMFS... the Atlantic commercial shark fisheries (sandbar sharks, non-sandbar large coastal sharks, blue sharks, porbeagle sharks, and pelagic sharks (other than porbeagle and blue sharks), non-blacknose small coastal...

  15. 76 FR 65673 - Atlantic Highly Migratory Species; Atlantic Shark Management Measures; Correction

    Science.gov (United States)

    2011-10-24

    ... Species; Atlantic Shark Management Measures; Correction AGENCY: National Marine Fisheries Service (NMFS... several Atlantic shark stocks and announced NMFS' intent to amend the 2006 Consolidated Highly Migratory Species (HMS) Fishery Management Plan (FMP) via the rulemaking process to rebuild these shark stocks and...

  16. 78 FR 54195 - Atlantic Highly Migratory Species; Atlantic Commercial Shark Fisheries

    Science.gov (United States)

    2013-09-03

    ... Species; Atlantic Commercial Shark Fisheries AGENCY: National Marine Fisheries Service (NMFS), National.... SUMMARY: NMFS is transferring 68 metric tons (mt) dressed weight (dw) of non-blacknose small coastal shark... adjustments, and applies to commercial Atlantic shark permitted vessels. DATES: The quota transfer is...

  17. 75 FR 250 - Atlantic Highly Migratory Species; Atlantic Commercial Shark Management Measures

    Science.gov (United States)

    2010-01-05

    ...; Atlantic Commercial Shark Management Measures AGENCY: National Marine Fisheries Service (NMFS), National... sandbar sharks, non-sandbar large coastal sharks (LCS), small coastal sharks (SCS), and pelagic sharks based on any over- and/or underharvests experienced during the 2008 and 2009 Atlantic commercial shark...

  18. 78 FR 52487 - Atlantic Highly Migratory Species; 2014 Atlantic Shark Commercial Fishing Season

    Science.gov (United States)

    2013-08-23

    ... Species; 2014 Atlantic Shark Commercial Fishing Season AGENCY: National Marine Fisheries Service (NMFS... season for the Atlantic commercial shark fisheries. Quotas would be adjusted as allowable based on any..., fishing opportunities for commercial shark fishermen in all regions and areas. The proposed measures could...

  19. 76 FR 53652 - Atlantic Highly Migratory Species; Atlantic Shark Management Measures

    Science.gov (United States)

    2011-08-29

    ... Species; Atlantic Shark Management Measures AGENCY: National Marine Fisheries Service (NMFS), National... sharks in the family Sphyrnidae (except for Sphyrna tiburo) and oceanic whitetip sharks (Carcharhinus...-427-8503 or by fax: 301-713-1917. SUPPLEMENTARY INFORMATION: The U.S. Atlantic shark fisheries are...

  20. Influence of the Atlantic subpolar gyre on the thermohaline circulation.

    Science.gov (United States)

    Hátún, Hjálmar; Sandø, Anne Britt; Drange, Helge; Hansen, Bogi; Valdimarsson, Hedinn

    2005-09-16

    During the past decade, record-high salinities have been observed in the Atlantic Inflow to the Nordic Seas and the Arctic Ocean, which feeds the North Atlantic thermohaline circulation (THC). This may counteract the observed long-term increase in freshwater supply to the area and tend to stabilize the North Atlantic THC. Here we show that the salinity of the Atlantic Inflow is tightly linked to the dynamics of the North Atlantic subpolar gyre circulation. Therefore, when assessing the future of the North Atlantic THC, it is essential that the dynamics of the subpolar gyre and its influence on the salinity are taken into account.

  1. Aberrant astrocyte Ca2+signals "AxCa signals" exacerbate pathological alterations in an Alexander disease model.

    Science.gov (United States)

    Saito, Kozo; Shigetomi, Eiji; Yasuda, Rei; Sato, Ryuichi; Nakano, Masakazu; Tashiro, Kei; Tanaka, Kenji F; Ikenaka, Kazuhiro; Mikoshiba, Katsuhiko; Mizuta, Ikuko; Yoshida, Tomokatsu; Nakagawa, Masanori; Mizuno, Toshiki; Koizumi, Schuichi

    2018-01-31

    Alexander disease (AxD) is a rare neurodegenerative disorder caused by gain of function mutations in the glial fibrillary acidic protein (GFAP) gene. Accumulation of GFAP proteins and formation of Rosenthal fibers (RFs) in astrocytes are hallmarks of AxD. However, malfunction of astrocytes in the AxD brain is poorly understood. Here, we show aberrant Ca 2+ responses in astrocytes as playing a causative role in AxD. Transcriptome analysis of astrocytes from a model of AxD showed age-dependent upregulation of GFAP, several markers for neurotoxic reactive astrocytes, and downregulation of Ca 2+ homeostasis molecules. In situ AxD model astrocytes produced aberrant extra-large Ca 2+ signals "AxCa signals", which increased with age, correlated with GFAP upregulation, and were dependent on stored Ca 2+ . Inhibition of AxCa signals by deletion of inositol 1,4,5-trisphosphate type 2 receptors (IP3R2) ameliorated AxD pathogenesis. Taken together, AxCa signals in the model astrocytes would contribute to AxD pathogenesis. © 2018 Wiley Periodicals, Inc.

  2. Modulation of Atlantic Aerosols by the Madden-Julian Oscillation

    Science.gov (United States)

    Tian, B.; Waliser, D. E.; Kahn, Ralph A.; Wong, S.

    2010-01-01

    Much like the better-known EI Nino-Southern Oscillation, the Madden-Julian Oscillation (MJO) is a global-scale atmospheric phenomenon. The MJO involves periodic, systematic changes in the distribution of clouds and precipitation over the western Pacific and Indian oceans, along with differences in wind intensity over even more extensive areas, including the north and subtropical Atlantic Ocean. The lead authors of this paper developed a sophisticated mathematical technique for mapping the spatial and temporal behavior of changes in the atmosphere produced by the MJO. In a previous paper, we applied this technique to search for modulation of airborne particle amount in the eastern hemisphere associated with the "wet" (cloudy) vs. "dry" phases of the MJO. The study used primarily AVHRR, MODIS, and TOMS satellite-retrieved aerosol amount, but concluded that other factors, such as cloud contamination of the satellite signals, probably dominated the observed variations. The current paper looks at MJO modulation of desert dust transport eastward across the Atlantic from northern Africa, a region much less subject to systematic cloud contamination than the eastern hemisphere areas studied previously. In this case, a distinct aerosol signal appears, showing that dust is transported westward much more effectively during the MJO phase that favors westward-flowing wind, and such transport is suppressed when the MJO reduces these winds. Aside form the significant achievement in identifying such an effect, the result implies that an important component of global dust transport can be predicted based on the phase of the MJO. As a consequence, the impact of airborne dust on storm development in the Atlantic, and on dust deposition downwind of the desert sources, can also be predicted and more accurately modeled.

  3. A century of Amazon burning driven by Atlantic climate

    Science.gov (United States)

    Makou, M.; Thompson, L. G.; Davis, M. E.; Eglinton, T. I.

    2011-12-01

    Very little is known about annual burning trends in the Amazon Basin prior to remote sensing of fires beginning in the late 1970's. Fires reduce Amazon forest biomass and species richness, release pollutant aerosols, and impact the carbon cycle, compelling further investigation of fire-climate dynamics. We measured organic compounds derived from vegetation burning in ice core samples from the Quelccaya Ice Cap in Peru at better than annual resolution to reconstruct wet and dry season burning throughout the Twentieth Century. Variations in the abundance of methyl hexadecanoate, which is produced by thermal alteration of vascular plant alkanoic acids, were used as a proxy for past fire activity. Concentrations of this compound in Quelccaya ice varied strongly on seasonal, interannual, and decadal time scales over the last 100 years, with high-amplitude dry season variability and muted, decadal-scale changes in wet season fire activity. Decade-long periods of repeatedly enhanced burning occurred during the 1930's and 1960's when dry season precipitation was perpetually reduced, as evidenced by low stages of the Rio Negro. These decadal trends suggest that changes in dry season precipitation drive fire activity in the western Amazon and highlight the potential of Amazon forests to undergo repeated strong burning. Fires occurred during years when sea surface temperatures (SSTs) in the north tropical Atlantic were elevated and the north-south tropical Atlantic SST gradient was enhanced; this SST pattern likely displaced the intertropical convergence zone northward, driving subsidence and drought in the western and southern Amazon basin. Thus, our novel ice core record suggests that Amazon forest fire activity during the Twentieth Century was driven primarily by Atlantic climate processes, and future forest health will depend heavily on the evolution of tropical climate.

  4. Widespread and synchronous change in deep-ocean circulation in the North and South Atlantic during the Late Cretaceous

    OpenAIRE

    Robinson, S. A.; Vance, D.

    2012-01-01

    Modern thermohaline circulation plays a role in latitudinal heat transport and in deep-ocean ventilation, yet ocean circulation may have functioned differently during past periods of extreme warmth, such as the Cretaceous. The Late Cretaceous (100–65 Ma) was an important period in the evolution of the North Atlantic Ocean, characterized by opening ocean gateways, long-term climatic cooling and the cessation of intermittent periods of anoxia (oceanic anoxic events, OAEs). However, how these ph...

  5. The role of the subtropical North Atlantic water cycle in recent US extreme precipitation events

    Science.gov (United States)

    Li, Laifang; Schmitt, Raymond W.; Ummenhofer, Caroline C.

    2017-04-01

    The role of the oceanic water cycle in the record-breaking 2015 warm-season precipitation in the US is analyzed. The extreme precipitation started in the Southern US in the spring and propagated northward to the Midwest and the Great Lakes in the summer of 2015. This seasonal evolution of precipitation anomalies represents a typical mode of variability of US warm-season precipitation. Analysis of the atmospheric moisture flux suggests that such a rainfall mode is associated with moisture export from the subtropical North Atlantic. In the spring, excessive precipitation in the Southern US is attributable to increased moisture flux from the northwestern portion of the subtropical North Atlantic. The North Atlantic moisture flux interacts with local soil moisture which enables the US Midwest to draw more moisture from the Gulf of Mexico in the summer. Further analysis shows that the relationship between the rainfall mode and the North Atlantic water cycle has become more significant in recent decades, indicating an increased likelihood of extremes like the 2015 case. Indeed, two record-high warm-season precipitation events, the 1993 and 2008 cases, both occurred in the more recent decades of the 66 year analysis period. The export of water from the North Atlantic leaves a marked surface salinity signature. The salinity signature appeared in the spring preceding all three extreme precipitation events analyzed in this study, i.e. a saltier-than-normal subtropical North Atlantic in spring followed by extreme Midwest precipitation in summer. Compared to the various sea surface temperature anomaly patterns among the 1993, 2008, and 2015 cases, the spatial distribution of salinity anomalies was much more consistent during these extreme flood years. Thus, our study suggests that preseason salinity patterns can be used for improved seasonal prediction of extreme precipitation in the Midwest.

  6. Reanalysis of climate influences on Atlantic tropical cyclone activity using cluster analysis

    Science.gov (United States)

    Boudreault, Mathieu; Caron, Louis-Philippe; Camargo, Suzana J.

    2017-04-01

    We analyze, using Poisson regressions, the main climate influences on North Atlantic tropical cyclone activity. The analysis is performed using not only various time series of basin-wide storm counts but also various series of regional clusters, taking into account shortcomings of the hurricane database through estimates of missing storms. The analysis confirms that tropical cyclones forming in different regions of the Atlantic are susceptible to different climate influences. We also investigate the presence of trends in these various time series, both at the basin-wide and cluster levels, and show that, even after accounting for possible missing storms, there remains an upward trend in the eastern part of the basin and a downward trend in the western part. Using model selection algorithms, we show that the best model of Atlantic tropical cyclone activity for the recent past is constructed using Atlantic sea surface temperature and upper tropospheric temperature, while for the 1878-2015 period, the chosen covariates are Atlantic sea surface temperature and El Niño-Southern Oscillation. We also note that the presence of these artificial trends can impact the selection of the best covariates. If the underlying series shows an upward trend, then the mean Atlantic sea surface temperature captures both interannual variability and the upward trend, artificial or not. The relative sea surface temperature is chosen instead for stationary counts. Finally, we show that the predictive capability of the statistical models investigated is low for U.S. landfalling hurricanes but can be considerably improved when forecasting combinations of clusters whose hurricanes are most likely to make landfall.

  7. Hydrology of surface waters and thermohaline circulation during the last glacial period; Hydrologie des eaux de surface et circulation thermohaline au cours de la derniere periode glaciaire

    Energy Technology Data Exchange (ETDEWEB)

    Vidal, L.

    1996-03-27

    Sedimentological studies on oceanic cores from the north Atlantic have revealed, over the last glacial period, abrupt climatic changes with a periodicity of several thousand years which contrasts strongly with the glacial-interglacial periodicity (several tens of thousand years). These periods of abrupt climate changes correspond to massive icebergs discharges into the north Atlantic. The aim of this work was to study the evolution of the thermohaline circulation in relation to these episodic iceberg discharges which punctuated the last 60 ka. To reconstruct the oceanic circulation in the past, we have analysed oxygen and carbon stable isotopes on benthic foraminifera from north Atlantic deep-sea cores. First of all, the higher temporal resolution of sedimentary records has enabled us to establish a precise chrono-stratigraphy for the different cores. Then, we have shown the close linkage between surface water hydrology and deep circulation, giving evidence of the sensibility of thermohaline circulation to melt water input in the north Atlantic ocean. Indeed, changes in deep circulation are synchronous from those identified in surface waters and are recorded on a period which lasted {approx} 1500 years. Deep circulation reconstructions, before and during a typical iceberg discharge reveal several modes of circulation linked to different convection sites at the high latitudes of the Atlantic basin. Moreover, the study of the last glacial period gives the opportunity to differentiate circulation changes due to the external forcing (variations of the orbital parameters) and those linked to a more local forcing (icebergs discharges). 105 refs., 50 figs., 14 tabs., 4 appends.

  8. Mg/Ca-temperature calibration for the benthic foraminifera Melonis barleeanum and Melonis pompilioides

    Science.gov (United States)

    Hasenfratz, Adam P.; Schiebel, Ralf; Thornalley, David J. R.; Schönfeld, Joachim; Jaccard, Samuel L.; Martínez-García, Alfredo; Holbourn, Ann; Jennings, Anne E.; Kuhnt, Wolfgang; Lear, Caroline H.; Marchitto, Thomas M.; Quillmann, Ursula; Rosenthal, Yair; Yu, Jimin; Haug, Gerald H.

    2017-11-01

    An important tool for deep-sea temperature reconstruction is Mg/Ca paleothermometry applied to benthic foraminifera. Foraminifera of the genus Melonis appear to be promising candidates for temperature reconstructions due to their wide geographical and bathymetric distribution, and their infaunal habitat, which was suggested to reduce secondary effects from carbonate ion saturation (Δ[CO32-]). Here, we make substantial advances to previous calibration efforts and present new multi-lab Mg/Ca data for Melonis barleeanum and Melonis pompilioides from more than one hundred core top samples spanning in situ bottom temperatures from -1 to 16 °C, coupled with morphometric analyses of the foraminifer tests. Both species and their morphotypes seem to have a similar response of Mg/Ca to growth temperature. Compilation of new and previously published data reveals a linear dependence of temperature on Mg/Ca, with a best fit of Mg/Ca (mmol/mol) = 0.113 ± 0.005 ∗ BWT (°C) + 0.792 ± 0.036 (r2 = 0.81; n = 120; 1σ SD). Salinity, bottom water Δ[CO32-], and varying morphotypes have no apparent effect on the Mg/Ca-temperature relationship, but pore water Δ[CO32-] might have had an influence on some of the samples from the tropical Atlantic.

  9. Request for proposal from C & AG empanelled CA firms

    Indian Academy of Sciences (India)

    IAS

    ... undertake the audit of an international publishing agency with whom the Academy has a co-publication agreement. This notice is to seek proposal from C & AG empanelled CA firms who are familiar with the auditing of online subscription of journals, periodicals etc and who have knowledge of activities of an organization ...

  10. Atlantic coastal plain geothermal test holes, Virginia: hole completion reports

    Energy Technology Data Exchange (ETDEWEB)

    Cobb, L.B.; Radford, L.; Glascock, M.

    1979-03-01

    A description of the Atlantic Coastal Plain Geothermal Drilling Program and data for the following geothermal test holes drilled in Virginia are summarized: Creeds, Norfolk Naval Base, Langley Air Force Base, Wattsville, Withams, and Atlantic.

  11. Visual quasi-periodicity

    NARCIS (Netherlands)

    Pogalin, E.; Smeulders, A.W.M.; Thean, A.H.C.

    2008-01-01

    Periodicity is at the core of the recognition of many actions. This paper takes the following steps to detect and measure periodicity. 1) We establish a conceptual framework of classifying periodicity in 10 essential cases, the most important of which are flashing (of a traffic light), pulsing (of

  12. Seasonal predictability of the North Atlantic Oscillation

    Science.gov (United States)

    Vellinga, Michael; Scaife, Adam

    2015-04-01

    Until recently, long-range forecast systems showed only modest levels of skill in predicting surface winter climate around the Atlantic Basin and associated fluctuations in the North Atlantic Oscillation at seasonal lead times. Here we use a new forecast system to assess seasonal predictability of winter North Atlantic climate. We demonstrate that key aspects of European and North American winter climate and the surface North Atlantic Oscillation are highly predictable months ahead. We demonstrate high levels of prediction skill in retrospective forecasts of the surface North Atlantic Oscillation, winter storminess, near-surface temperature, and wind speed, all of which have high value for planning and adaptation to extreme winter conditions. Analysis of forecast ensembles suggests that while useful levels of seasonal forecast skill have now been achieved, key sources of predictability are still only partially represented and there is further untapped predictability. This work is distributed under the Creative Commons Attribution 3.0 Unported License together with an author copyright. This license does not conflict with the regulations of the Crown Copyright.

  13. Glacier maxima in Baffin Bay during the Medieval Warm Period coeval with Norse settlement.

    Science.gov (United States)

    Young, Nicolás E; Schweinsberg, Avriel D; Briner, Jason P; Schaefer, Joerg M

    2015-12-01

    The climatic mechanisms driving the shift from the Medieval Warm Period (MWP) to the Little Ice Age (LIA) in the North Atlantic region are debated. We use cosmogenic beryllium-10 dating to develop a moraine chronology with century-scale resolution over the last millennium and show that alpine glaciers in Baffin Island and western Greenland were at or near their maximum LIA configurations during the proposed general timing of the MWP. Complimentary paleoclimate proxy data suggest that the western North Atlantic region remained cool, whereas the eastern North Atlantic region was comparatively warmer during the MWP-a dipole pattern compatible with a persistent positive phase of the North Atlantic Oscillation. These results demonstrate that over the last millennium, glaciers approached their eventual LIA maxima before what is considered the classic LIA in the Northern Hemisphere. Furthermore, a relatively cool western North Atlantic region during the MWP has implications for understanding Norse migration patterns during the MWP. Our results, paired with other regional climate records, point to nonclimatic factors as contributing to the Norse exodus from the western North Atlantic region.

  14. Glacier maxima in Baffin Bay during the Medieval Warm Period coeval with Norse settlement

    Science.gov (United States)

    Young, Nicolás E.; Schweinsberg, Avriel D.; Briner, Jason P.; Schaefer, Joerg M.

    2015-01-01

    The climatic mechanisms driving the shift from the Medieval Warm Period (MWP) to the Little Ice Age (LIA) in the North Atlantic region are debated. We use cosmogenic beryllium-10 dating to develop a moraine chronology with century-scale resolution over the last millennium and show that alpine glaciers in Baffin Island and western Greenland were at or near their maximum LIA configurations during the proposed general timing of the MWP. Complimentary paleoclimate proxy data suggest that the western North Atlantic region remained cool, whereas the eastern North Atlantic region was comparatively warmer during the MWP—a dipole pattern compatible with a persistent positive phase of the North Atlantic Oscillation. These results demonstrate that over the last millennium, glaciers approached their eventual LIA maxima before what is considered the classic LIA in the Northern Hemisphere. Furthermore, a relatively cool western North Atlantic region during the MWP has implications for understanding Norse migration patterns during the MWP. Our results, paired with other regional climate records, point to nonclimatic factors as contributing to the Norse exodus from the western North Atlantic region. PMID:26665173

  15. Northern North Atlantic Sea Surface Height and Ocean Heat Content Variability

    Science.gov (United States)

    Hakkinen, Sirpa; Rhines, Peter; Worthen, Denise L.

    2013-01-01

    The evolution of nearly 20 years of altimetric sea surface height (SSH) is investigated to understand its association with decadal to multidecadal variability of the North Atlantic heat content. Altimetric SSH is dominated by an increase of about 14 cm in the Labrador and Irminger seas from 1993 to 2011, while the opposite has occurred over the Gulf Stream region over the same time period. During the altimeter period the observed 0-700 m ocean heat content (OHC) in the subpolar gyre mirrors the increased SSH by its dominantly positive trend. Over a longer period, 1955-2011, fluctuations in the subpolar OHC reflect Atlantic multidecadal variability (AMV) and can be attributed to advection driven by the wind stress ''gyre mode'' bringing more subtropical waters into the subpolar gyre. The extended subpolar warming evident in SSH and OHC during the altimeter period represents transition of the AMV from cold to warm phase. In addition to the dominant trend, the first empirical orthogonal function SSH time series shows an abrupt change 2009-2010 reaching a new minimum in 2010. The change coincides with the change in the meridional overturning circulation at 26.5N as observed by the RAPID (Rapid Climate Change) project, and with extreme behavior of the wind stress gyre mode and of atmospheric blocking. While the general relationship between northern warming and Atlantic meridional overturning circulation (AMOC) volume transport remains undetermined, the meridional heat and salt transport carried by AMOC's arteries are rich with decade-to-century timescale variability.

  16. Timing of last deglaciation in the Cantabrian Mountains (Iberian Peninsula; North Atlantic Region) based on in situ-produced 10Be exposure dating

    Science.gov (United States)

    Rodríguez-Rodríguez, Laura; Jiménez-Sánchez, Montserrat; Domínguez-Cuesta, María José; Rinterknecht, Vincent; Pallàs, Raimon; Aumaître, Georges; Bourlès, Didier L.; Keddadouche, Karim; Aster Team

    2017-09-01

    The Last Glacial Termination led to major changes in ice sheet coverage that disrupted global patterns of atmosphere and ocean circulation. Paleoclimate records from Iberia suggest that westerly episodes played a key role in driving heterogeneous climate in the North Atlantic Region. We used 10Be Cosmic Ray Exposure (CRE) dating to explore the glacier response of small mountain glaciers (ca. 5 km2) that developed on the northern slope of the Cantabrian Mountains (Iberian Peninsula), an area directly under the influence of the Atlantic westerly winds. We analyzed twenty boulders from three moraines and one rock glacier arranged as a recessional sequence preserved between 1150 and 1540 m above sea level (a.s.l.) in the Monasterio valley (Redes Natural Park). Results complement previous chronologic data based on radiocarbon and optically stimulated luminescence from the Monasterio valley, which suggest a local Glacial Maximum (local GM) prior to 33 ka BP and a long-standing glacier advance at 24 ka coeval to the global Last Glacial Maximum (LGM). Resultant 10Be CRE ages suggest a progressive retreat and thinning of the Monasterio glacier over the time interval 18.1-16.7 ka. This response is coeval with the Heinrich Stadial 1, an extremely cold and dry climate episode initiated by a weakening of the Atlantic Meridional Overturning Circulation (AMOC). Glacier recession continued through the Bølling/Allerød period as indicate the minimum exposure ages obtained from a cirque moraine and a rock glacier nested within this moraine, which yielded ages of 14.0 and 13.0 ka, respectively. Together, they suggest that the Monasterio glacier experienced a gradual transition from glacier to rock glacier activity as the AMOC started to strengthen again. Glacial evidence ascribable to the Younger Dryas cooling was not dated in the Monasterio valley, but might have occurred at higher elevations than evidence dated in this work. The evolution of former glaciers documented in the

  17. [Ca2+]i rise at in vitro maturation in bovine cumulus-oocyte complexes.

    Science.gov (United States)

    Silvestre, Francesco; Fissore, Rafael A; Tosti, Elisabetta; Boni, Raffaele

    2012-06-01

    An intracellular calcium ([Ca(2+)]i) rise has been described in cumulus-oocyte complexes (COCs) following luteinizing hormone (LH) exposure. Together with cAMP, Ca(2+) is a candidate signal for resumption of meiosis. Here, we analyzed if the most common hormones involved in oocyte maturation can induce the same Ca(2+) signal. In addition, we characterized the source of this signal. Immature, in vitro-matured, and roscovitine-meiotically arrested COCs were loaded with Fluo-4 AM, stimulated with hormones/growth factors, and tested for [Ca(2+)](i) variations in cumulus cells. Reagents known to inhibit or stimulate [Ca(2+)](i) rises were used to characterize these [Ca(2+)](i) dynamics. Finally, expression of LH receptors (LHRs) in COCs was analyzed by immunofluorescence. In immature COCs, follicle-stimulating hormone (FSH) elicited a single [Ca(2+)](i) rise that was higher than those induced by LH and growth hormone (GH), whereas epithelial growth factor failed to induce any changes in [Ca(2+)](i). The [Ca(2+)](i) rise induced by FSH was higher in immature COCs; was reduced in roscovitine-arrested, immature COCs; and was negligible in gonadotropin-induced, in vitro-matured COCs. In the case of spontaneous- and GH-matured COCs, however, FSH stimulation caused a lower [Ca(2+)](i) rise. The hormone-induced [Ca(2+)](i) rise was due to: (i) external Ca(2+) entry; (ii) intercellular communication; and (iii) intracellular Ca(2+) stores. Immunofluorescence revealed that LHRs were expressed throughout the cumulus cells. The above results show that: (i) gonadotropins and GH cause a [Ca(2+)](i) rise in cumulus cells; (ii) this [Ca(2+)](i) rise results from extra-, inter-, and intra-cellular cumulative Ca(2+) fluxes; and (iii) LHRs are distributed on either outer or inner cumulus cells. Copyright © 2012 Wiley Periodicals, Inc.

  18. Influence of the North Atlantic Oscillation on air pollution transport

    Directory of Open Access Journals (Sweden)

    T. Christoudias

    2012-01-01

    Full Text Available We examined the influence of the North Atlantic Oscillation (NAO on the atmospheric dispersion of pollution by computing the emission, transport and removal of idealized insoluble gaseous and water-soluble aerosol tracers, tagged by the continent of origin. We simulated a period of 50 yr (1960–2010, using the ECHAM5/MESSy1 atmospheric chemistry (EMAC general circulation model. The model accounts for anthropogenic, biogenic and biomass burning sources, removal of trace gases through OH oxidation, and precipitation, sedimentation and deposition of aerosols. The model is shown to reproduce the observed spatial features of the NAO, moisture transports and precipitation. During high NAO phase seasons the axis of maximum westerly North American trace gas transports extends relatively far to the north and east over Europe. The NAO phase is significantly correlated with North American insoluble gas and soluble aerosol tracer concentrations over the northwestern Atlantic Ocean and across northern Europe, and with European trace gases and aerosols over Africa and north of the Arctic circle. We find a strong anti-correlation between the phase of the NAO and European pollutant gas concentration over western and central Europe.

  19. An experimental study of the Atlantic variability on interdecadal timescales

    Directory of Open Access Journals (Sweden)

    M. Vincze

    2012-06-01

    Full Text Available A series of laboratory experiments has been carried out to model the basic dynamics of the multidecadal variability observed in North Atlantic sea surface temperature (SST records. According to the minimal numerical sector model introduced by te Raa and Dijkstra (2002, the three key components to excite such a low-frequency variability are rotation, meridional temperature gradient and additive thermal noise in the surface heat forcing. If these components are present, periodic perturbations of the overturning background flow are excited, leading to thermal Rossby mode like propagation of anomalous patches in the SST field. Our tabletop scale setup was built to capture this phenomenon, and to test whether the aforementioned three components are indeed sufficient to generate a low-frequency variability in the system. The results are compared to those of the numerical models, as well as to oceanic SST reanalysis records. To the best of our knowledge, the experiment described here is the very first to investigate the dynamics of the North Atlantic multidecadal variability in a laboratory-scale setup.

  20. Influence of Atlantic SST anomalies on the atmospheric circulation in the Atlantic-European sector

    Directory of Open Access Journals (Sweden)

    E. Kestenare

    2003-06-01

    Full Text Available Recent studies of observational data suggest that Sea Surface Temperature (SST anomalies in the Atlantic Ocean have a significant influence on the atmospheric circulation in the Atlantic-European sector in early winter and in spring. After reviewing this work and showing that the spring signal is part of a global air-sea interaction, we analyze for comparison an ensemble of simulations with the ECHAM4 atmospheric general circulation model in T42 resolution forced by the observed distribution of SST and sea ice, and a simulation with the ECHAM4/OPA8 coupled model in T30 resolution. In the two cases, a significant influence of the Atlantic on the atmosphere is detected in the Atlantic-European sector. In the forced mode, ECHAM4 responds to SST anomalies from early spring to late summer, and also in early winter. The forcing involves SST anomalies not only in the tropical Atlantic, but also in the whole tropical band, suggesting a strong ENSO influence. The modeled signal resembles that seen in the observations in spring, but not in early winter. In the coupled mode, the Atlantic SST only has a significant influence on the atmosphere in summer. Although the SST anomaly is confined to the Atlantic, the summer signal shows some similarity with that seen in the forced simulations. However, there is no counterpart in the observations.

  1. Rock Magnetic Properties Across Paleocene-Eocene Boundary Sediments from the North Atlantic, South Atlantic, and Eastern Pacific

    Science.gov (United States)

    Lippert, P. C.; Zachos, J.; Bohaty, S.; Quattlebaum, T.

    2004-12-01

    We present new rock magnetic data from Wilson Lake, NJ (N. Atlantic continental shelf), ODP Site 1262, (Walvis Ridge, S. Atlantic), and Lodo, CA (continental shelf, coastal California) in an effort to evaluate the comet-impact trigger hypothesis (Kent et al., 2003) for the carbon isotope excursion (CEI) associated with the Paleocene-Eocene Thermal Maximum (PETM). The comet-impact trigger hypothesis is based primarily on anomalous magnetic properties in outer shelf Paleocene-Eocene boundary sediments from the New Jersey continental margin; proponents of this hypothesis suggest these magnetic properties indicate the presence of extraterrestrial nanoparticles of magnetite. Our results suggest that these nanoparticles of magnetite may be terrestrial, not cosmic, in origin. Changes in magnetic hysteresis properties (e.g., Mr/Ms and Hc/Hcr) across the Wilson Lake section are similar to those from other regional stratigraphic sections (re: Kent et al., 2003), but similar changes are not observed at S. Atlantic or coastal California sites; thus, there may be a regional rather than global source of magnetic material. Squareness plots (Tauxe et al., 2003) and Day plots (Day, 1977) of hysteresis data suggest that Wilson Lake magnetite is single domain (SD flower structure to SD cubic), but the grain size of magnetite from the other two sites is mixed, possibly with a significant component of pseudo-single domain grains. Weak-field high temperature susceptibility experiments suggest that the primary magnetic mineral in these sections is magnetite. Low-temperature zero- and strong-field saturation isothermal remanent magnetization (SIRM) experiments indicate that the fine-grained magnetite is partially oxidized, probably to maghemite. More significant, however, the low-temperature experiments suggest that the fine-grained magnetite from the CIE portion of the Wilson Lake section may have a biogenic origin. Although it is clear that intact chains of magnetosomes are not

  2. The Atlantic Multidecadal Oscillation in models and observations

    NARCIS (Netherlands)

    Frankcombe, L.M.

    2010-01-01

    We use a simplified model of the North Atlantic ocean to study the Atlantic Multidecadal Oscillation (AMO), which is a low-frequency variation found in sea surface temperatures (SST) over the North Atlantic ocean. A mechanism for the AMO has previously been described; here we study the excitation of

  3. 77 FR 70551 - Highly Migratory Species; Atlantic Shark Management Measures

    Science.gov (United States)

    2012-11-26

    ... Part 635 Highly Migratory Species; Atlantic Shark Management Measures; Proposed Rule #0;#0;Federal...; Atlantic Shark Management Measures AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and... shark stock assessments that were completed from 2009 to 2012. The assessments for Atlantic blacknose...

  4. Impact of interbasin exchange on the Atlantic overturning circulation

    NARCIS (Netherlands)

    Weijer, W.; Ruijter, W.P.M. de; Dijkstra, H.A.; Leeuwen, P.J. van

    2000-01-01

    The thermohaline exchange between the Atlantic and the Southern Ocean is analyzed, using a data set based on WOCE hydrographic data. It is shown that the salt and heat transports brought about by the South Atlantic subtropical gyre play an essential role in the Atlantic heat and salt budgets. It

  5. Atlantic Canada : Dancing with whales

    Energy Technology Data Exchange (ETDEWEB)

    Reid, W.

    2003-03-03

    A major question in the Atlantic provinces that needs resolving concerns the how much waters and sea floors that can be considered protected area before disruption of industrial activity in the vicinity of those areas occurs, especially where there is potential for natural gas and crude oil. Another question that needs pondering relates to the amount of money that the federal government is willing to spend to study the effects on marine habitats resulting from this industrial activity. The consideration being given to a region called the Gully, as to whether it should be declared an official marine protected zone, brought these questions to the forefront. A canyon approximately 70 kilometres (km) long and 20 km wide, the Gully is a potentially resource-rich area located in deep water 300 km east of Cape Breton at the edge of the Scotian Shelf. A pilot project was implemented in 1998, but no clear decision has yet been made concerning the status of the Gully. According to a biology professor at Dalhousie University in Halifax, the Department of Fisheries and Oceans is busy obtaining the proper approvals for its designation as a fully protected area. The northern bottlenose whale can be found in this canyon. This professor advocates a ban on industrial activity in the vicinity of the Gully, as he believes that seismic surveys and exploratory drilling pose a danger to the whales. He would like to see more funding allocated to research programs. Companies conducting seismic surveys in the vicinity of the Gully have to comply with environmental standards.

  6. The American South in the Atlantic World

    DEFF Research Database (Denmark)

    "A refreshing and intriguing interdisciplinary examination of the ways in which the history and cultures of the American South have been largely shaped by forces beyond the geographical boundaries of the United States." --Allison Graham, author of Framing the South "This is an impressive collection......, emphasizing black and white racial binaries and outdated geographical boundaries, The American South and the Atlantic World seeks larger thematic and spatial contexts. This is the first book to focus explicitly on how contacts with the peoples, cultures, ideas, and economies of the Atlantic World have...... when there is growing emphasis on globalizing southern studies the collection both demonstrates and critiques the value of Atlantic World perspectives on the region. Equally important, the mix of case studies and state-of-the field essays combines the latest historical thinking on the South’s myriad...

  7. Simulated Atmospheric Response to the 2015 North Atlantic SST Cold Blob

    Science.gov (United States)

    Mecking, Jennifer; Drijfhout, Sybren; Hirshi, Joel; Blaker, Adam; Duchez, Aurelie

    2017-04-01

    In the summer of 2015 central Europe experienced a major heat wave which in the months before was preceded by the development of anomalously cold sea surface temperatures in the northern North Atlantic. A previous study has shown that the cold ocean anomaly preceded a pronounced southward deviation of the Jet Stream path in early June which favoured the development of the heat wave over central Europe. However, whether the cold SST anomaly in the North Atlantic was the cause of the change in the atmospheric circulation is not yet clear. This study aims to further investigate the connection between the Atlantic cold blob of 2015 and the heat wave over central Europe through the use of a state-of-the-art coupled climate model, HadGEM3. The coupled model is initialized with 3D anomalies for temperature and salinity, obtained from an ocean-only hindcast run for the 1958 to 2016 period. The ocean-only model simulates the cold blob event well. Also, it is nearly the same model (NEMO ORCA025) as the ocean component of HadGEM3, implying that using ORCA025 T and S field minimizes the adjustment/initialisation shock compared to assimilating observations. Two different model ensembles are generated: 1) Applying the initial temperature and salinity anomalies globally (GLOBAL) and 2) applying the initial temperature and salinity anomalies only to the North Atlantic (ATLANTIC). In both GLOBAL and ATLANTIC the application of the ocean anomalies leads to a heat wave over central Europe for the ensemble mean. The GLOBAL ensemble shows a stronger signal for the central European heat wave than ATLANTIC. This suggests that remote signals (i.e. from outside the North Atlantic) likely helped to enhance the heat wave. Compared to observations, our model results all favour a heat wave that is shifted too far east. Further investigations of the mechanisms behind the heat wave as well as some of the difficulties in simulating the correct location of the heat wave will be discussed.

  8. Changes in Equatorial Atlantic Ocean Thermohaline Circulation Across the Mid-Pleistocene Transition

    Science.gov (United States)

    Yehudai, M.; Kim, J.; Seguí, M. J.; Goldstein, S. L.; Pena, L. D.; Haynes, L.; Hoenisch, B.; Farmer, J. R.; Ford, H. L.; Raymo, M. E.; Bickert, T.

    2016-12-01

    The Mid-Pleistocene Transition (MPT) marked a change in the duration of glacial-interglacial cycles from 41 to 100kyr between 1.3-0.7 Ma. A recent study (Pena and Goldstein, Science, 2014) from the Southern Atlantic Ocean found evidence for major disruptions in the global thermohaline circulation (THC) between MIS 25-21 ( 950-850ka), which may have triggered intensified glacial periods and the onset of the 100 kyr cycles. We report new Nd isotope data on Fe-Mn oxide encrusted foraminifera and fish debris from ODP Site 926 (3.719N, 42.908W, 3598m) between 1.2-0.4 Ma, in order to evaluate changes in the THC in the equatorial Atlantic, through comparison with North and South Atlantic sites. The ODP 926 ɛNd values fall in-between those in the North Atlantic (DSDP 607) and South Atlantic (ODP 1088 and 1090) throughout the studied interval, consistent with mixing between northern and southern end-members, and supporting the interpretation that the data represent the THC signal at this site. Pre-MPT data show smaller glacial-interglacial differences compared to the greater post-MPT glacial-interglacial variability. As Pena and Goldstein (2014) observed in the South Atlantic, during MIS 23 at 900 ka, ɛNd values do not shift significantly toward North Atlantic more negative values, consistent with a weak THC through this critical weak interglacial. Comparing ODP 926 and DSDP 607 data, ɛNd values converge during most interglacial peaks (excepting MIS 23) and diverge otherwise. This observation indicates that northern-sourced water masses dominate the site during peak interglacials, and confirms that the THC has been strongest during peak interglacials throughout the studied interval. Otherwise, diverging ɛNd values indicate a stronger southern-source signal and weaker northern-source signal at the ODP 926 site. This confirms that there was an active but variable THC system before, during, and after the MPT, with stronger deep water export from the North Atlantic during

  9. Deglacial Tropical Atlantic subsurface warming links ocean circulation variability to the West African Monsoon.

    Science.gov (United States)

    Schmidt, Matthew W; Chang, Ping; Parker, Andrew O; Ji, Link; He, Feng

    2017-11-13

    Multiple lines of evidence show that cold stadials in the North Atlantic were accompanied by both reductions in Atlantic Meridional Overturning Circulation (AMOC) and collapses of the West African Monsoon (WAM). Although records of terrestrial change identify abrupt WAM variability across the deglaciation, few studies show how ocean temperatures evolved across the deglaciation. To identify the mechanism linking AMOC to the WAM, we generated a new record of subsurface temperature variability over the last 21 kyr based on Mg/Ca ratios in a sub-thermocline dwelling planktonic foraminifera in an Eastern Equatorial Atlantic (EEA) sediment core from the Niger Delta. Our subsurface temperature record shows abrupt subsurface warming during both the Younger Dryas (YD) and Heinrich Event 1. We also conducted a new transient coupled ocean-atmosphere model simulation across the YD that better resolves the western boundary current dynamics and find a strong negative correlation between AMOC strength and EEA subsurface temperatures caused by changes in ocean circulation and rainfall responses that are consistent with the observed WAM change. Our combined proxy and modeling results provide the first evidence that an oceanic teleconnection between AMOC strength and subsurface temperature in the EEA impacted the intensity of the WAM on millennial time scales.

  10. Oceanographic temperature, salinity, nitrate, phosphate, silicate, primary productivity, pigments, pCO2 and other measurements collected using bottle and CTD from multiple platforms in the North Atlantic during 1988 to 2006 (NODC Accession 0032053)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Chemical, biological, and physical profile data collected as part of the Bermuda-Atlantic Time Series Study (BATS) for the period 1988-December 2006 at Bermuda...

  11. Spatial and temporal trends of BFRs in Atlantic cod and polar cod in the North-East Atlantic

    Energy Technology Data Exchange (ETDEWEB)

    Bytingsvik, J.; Gaustad, H.; Pettersvik Salmer, M.; Soermo, E.G.; Munro Jenssen, B. [Norwegian Univ. of Science and Technology, Dept. of Biology, Trondheim (Norway); Baek, K.; Foereid, S. [Norwegian School of Veterinary Science, Oslo (Norway); Ruus, A. [Norwegian Insitute for Water Research, Oslo (Norway); Utne Skaare, J. [National Veterinary Institute, Oslo (Norway)

    2004-09-15

    in Atlantic cod from Hvaler in the period 1998-2003.

  12. Carbachol-induced [Ca2+]i oscillations in single smooth muscle cells of guinea-pig ileum.

    Science.gov (United States)

    Kohda, M; Komori, S; Unno, T; Ohashi, H

    1996-04-15

    1. Changes in cytosolic Ca2+ concentration ([Ca2+]i) produced by carbachol (CCh) were measured in single smooth muscle cells of guinea-pig ileum using a Ca(2+)-sensitive fluorescent dye, fura-2, to clarify the underlying mechanisms of muscarinic [Ca2+]i oscillations. 2. Half of the cells, when exposed to 0.2 microM CCh, exhibited repeated changes in [Ca2+]i giving a serrated appearance. The oscillatory changes in [Ca2+]i were very similar to those evoked by increasing extracellular K(+) concentration ([K+]o) to 30 mM, which were abolished by removal of extracellular Ca2+, nifedipine and La3+, but remained unchanged after depletion of internal Ca2+ stores with cyclopiazonic acid, thapsigargin and ryanodine. 3. Every individual [Ca2+]i oscillation was just like a [Ca2+]i increase generated spontaneously in about 8% of cells or triggered by an action potential evoked by a current pulse in current-clamped cells. 4. In the remaining half of the cells exposed to 0.2 microM CCh, slower [Ca2+]i oscillations were elicited and every individual [Ca2+]i oscillation was always preceded by the fast brief increase in [Ca2+]i. 5. [Ca2+]i oscillations elicited by 2 microM CCh were temporally and functionally distinct from those induced by high [K+]o. They were more or less regular in the periodicity and pattern, comprised pacemaker potential-like [Ca2+]i increases or sinusoidal types of [Ca2+]i increases, and could be elicited even in 100 mM K+(o). 6. Removal of extracellular Ca2+ or application of nifedipine, methoxyverapamil (D600), diltiazem or La3+ during CCh (2 micro M)-induced [Ca2+]i oscillations caused them to disappear. In cells i which internal Ca2+ stores were depleted, 2 microM CCh did not evoke [Ca2+]i oscillations but occasionally induced single or repeated generation of the increase in [Ca2+]i with a serrated appearance. 7. The results indicate that CCh can induce two types of [Ca2+]i oscillation in guinea-pig ileal smooth muscle cells; one arises from Ca2+ influx

  13. CARINA: nutrient data in the Atlantic Ocean

    Directory of Open Access Journals (Sweden)

    T. Tanhua

    2009-11-01

    Full Text Available Data on carbon and carbon-relevant hydrographic and hydrochemical parameters from previously non-publicly available cruise data sets in the Arctic, Atlantic and Southern Ocean have been retrieved and merged to a new database: CARINA (CARbon IN the Atlantic. These data have gone through rigorous quality control (QC procedures to assure the highest possible quality and consistency. The data for most of the measured parameters in the CARINA data base were objectively examined in order to quantify systematic differences in the reported values, i.e. secondary quality control. Systematic biases found in the data have been corrected in the data products, i.e. three merged data files with measured, calculated and interpolated data for each of the three CARINA regions; Arctic Mediterranean Seas, Atlantic and Southern Ocean. Out of a total of 188 cruise entries in the CARINA database, 98 were conducted in the Atlantic Ocean and of these 84 cruises report nitrate values, 79 silicate, and 78 phosphate. Here we present details of the secondary QC for nutrients for the Atlantic Ocean part of CARINA. Procedures of quality control, including crossover analysis between cruises and inversion analysis of all crossover data are briefly described. Adjustments were applied to the nutrient values for 43 of the cruises in the Atlantic Ocean region. With these adjustments the CARINA database is consistent both internally as well as with GLODAP data, an oceanographic data set based on the World Hydrographic Program in the 1990s (Key et al., 2004. Based on our analysis we estimate the internal accuracy of the CARINA-ATL nutrient data to be: nitrate 1.5%; phosphate 2.6%; silicate 3.1%. The CARINA data are now suitable for accurate assessments of, for example, oceanic carbon inventories and uptake rates and for model validation.

  14. Inflow of Atlantic-origin waters to the Barents Sea along glacial troughs

    Directory of Open Access Journals (Sweden)

    Gennady G. Matishov

    2009-09-01

    Full Text Available This paper discusses the role of glacial shelf topography in the formation of general oceanological and biological mechanisms in the Barents Sea. Analysis of geomorphological data and oceanographic observations obtained on board MMBI research vessels in 2001-08 has shown that: fluxes of Atlantic-origin waters pass along glacial troughs; the inflow of Atlantic waters to the Barents Sea from the west increased from 2001 till 2007, although this advection began to weaken in 2008; vertical and horizontal thermohaline gradients intensified during the investigated period; a warm period similar to that of the 1930s was observed in the Barents Sea at the beginning of the 21st century.

  15. Proto-historic and Historical Atlantic Navigation: Archaeological Evidence from the Azores

    Science.gov (United States)

    Ribeiro, Nuno; Joaquinito, Anabela; Pimenta, Fernando; Sauren, Herbert; Rodrigues, António Félix; Costa, Antonieta; Pereira, António Sérgio; Juliano, Maria de Fraga; Fernandes, Joaquim; Freitas, Ricardo; Ventura, Ricardo; Tirapicos, Luís

    2015-05-01

    This paper presents unpublished data on archaeological sites located in the Azores Islands that suggests the possibility of sailing in ancient times in the Atlantic, namely in the Proto-historic and Roman periods. Several structures, identified as hypogea, are reminiscent of Phoenician sanctuaries and, in their architecture, seem to represent the goddess Tanit. In addition, results of the epigraphic analysis of an inscribed stone, are presented wherein the "god of the Dacians" is mentioned, suggesting their presence in the islands during the Roman period. Overall, these preliminary finds raise new questions regarding the pre-Portuguese occupation of the archipelago as well as pre-compass navigation in the Atlantic, possibly using the stars.

  16. Multi-species coral Sr/Ca-based sea-surface temperature reconstruction using Orbicella faveolata and Siderastrea siderea from the Florida Straits

    Science.gov (United States)

    Flannery, Jennifer A.; Richey, Julie N.; Thirumalai, Kaustubh; Poore, Richard Z.; DeLong, Kristine L.

    2017-01-01

    We present new, monthly-resolved Sr/Ca-based sea-surface temperature (SST) records from two species of massive coral, Orbicella faveolata and Siderastrea siderea, from the Dry Tortugas National Park, FL, USA (DTNP). We combine these new records with published data from three additional S. siderea coral colonies to generate a 278-year long multi-species stacked Sr/Ca-SST record from DTNP. The composite record of mean annual Sr/Ca-SST at DTNP shows pronounced decadal-scale variability with a range of 1 to 2°C. Notable cool intervals in the Sr/Ca-derived SST lasting about a decade centered at ~1845, ~1935, and ~1965 are associated with reduced summer Sr/Ca-SST (monthly maxima < 29°C), and imply a reduction in the spatial extent of the Atlantic Warm Pool (AWP). There is significant coherence between the composite DTNP Sr/Ca-SST record and the Atlantic Multidecadal Oscillation (AMO) index, with the AMO lagging Sr/Ca-SST at DTNP by 9 years. Low frequency variability in the Gulf Stream surface transport, which originates near DTNP, may provide a link for the lagged relationship between multidecadal variability at DTNP and the AMO.

  17. A reconstruction of sea surface warming in the northern North Atlantic during MIS 3 ice-rafting events

    NARCIS (Netherlands)

    Jonkers, L.; Moros, M.; Prins, M.A.; Dokken, T.; Dahl, C. A.; Dijkstra, N.; Perner, K.; Brummer, G.J.A.

    2010-01-01

    Marine isotope stage 3 (29-59 kyr BP) is characterised by rapid shifts from cold stadial to warm interstadial periods, which may be linked to changes in the vigour of the Atlantic Meridional Overturning Circulation due to variable freshwater input by melting ice. Here we present two northern North

  18. Clinical Significance of Serum HE4, CA125, CA724, and CA19-9 in Patients With Endometrial Cancer.

    Science.gov (United States)

    Bian, Jing; Sun, Xiaoxu; Li, Bo; Ming, Liang

    2017-08-01

    Serum markers with increased sensitivity and specificity for endometrial cancer are required. To date, no good marker has met this standard. The aims of our study were to evaluate the utility of tumor markers HE4, CA125, CA724, and CA19-9 as potential markers in patients diagnosed with endometrial cancer. Blood samples from 105 patients with endometrial cancer and 87 healthy women were analyzed by Roche electrochemiluminescent immunoassay, and serum values were measured for the following biomarkers: HE4, CA125, CA724, and CA19-9. Serum HE4, CA125, CA724, and CA19-9 concentrations were significantly higher in patients with endometrial cancer, compared with controls ( P endometrial cancer, HE4 had higher sensitivity (58%), positive predictive value (60%), and negative predictive value (67%) than any other single tumor marker, and in the combination of HE4, CA125, CA724, and CA19-9, the sensitivity and positive predictive values reached 59.1% and 88%, respectively. Meanwhile, the receiver operating characteristic area under the curve of the combination of the 4 markers was significantly increased than any other group, either in stage I or in stage II to IV cases. HE4 and CA125 both correlate with advanced age; in addition, HE4 was related to pathology subtypes and positive adnexal involvement, CA125 was related to International Federation of Gynecology and Obstetrics stage, CA19-9 was related to International Federation of Gynecology and Obstetrics stage, and CA724 was correlated with positive lymph node. Combination of HE4, CA125, CA724, and CA19-9 has the highest value in diagnosing endometrial cancer, and they can be a useful tissue immune marker for patients with endometrial cancer.

  19. 75 FR 27219 - Fisheries of the Northeastern United States; Atlantic Deep-Sea Red Crab Fisheries; 2010 Atlantic...

    Science.gov (United States)

    2010-05-14

    ... United States; Atlantic Deep-Sea Red Crab Fisheries; 2010 Atlantic Deep-Sea Red Crab Specifications...), Commerce. ACTION: Final rule. SUMMARY: NMFS issues final specifications for the 2010 Atlantic deep- sea red... document is also accessible via the Internet at http://www.nefmc.org . NMFS prepared a Final Regulatory...

  20. Volcanic forcing of the North Atlantic Oscillation over the last 2,000 years

    Science.gov (United States)

    Breitenbach, Sebastian F. M.; Ridley, Harriet E.; Lechleitner, Franziska A.; Asmerom, Yemane; Rehfeld, Kira; Prufer, Keith M.; Kennett, Douglas J.; Aquino, Valorie V.; Polyak, Victor; Goswami, Bedartha; Marwan, Norbert; Haug, Gerald H.; Baldini, James U. L.

    2015-04-01

    The North Atlantic Oscillation (NAO) is a principal mode of atmospheric circulation in the North Atlantic realm (Hurrell et al. 2003) and influences rainfall distribution over Europe, North Africa and North America. Although observational data inform us on multi-annual variability of the NAO, long and detailed paleoclimate datasets are required to understand the mechanisms and full range of its variability and the spatial extent of its influence. Chronologies of available proxy-based NAO reconstructions are often interdependent and cover only the last ~1,100 years, while longer records are characterized by low sampling resolution and chronological constraints. This complicates the reconstruction of regional responses to NAO changes. We present data from a 2,000 year long sub-annual carbon isotope record from speleothem YOK-I from Yok Balum Cave, Belize, Central America. YOK-I has been extensively dated using U-series (Kennett et al. 2012). Monitoring shows that stalagmite δ13C in Yok Balum cave is governed by infiltration changes associated with tropical wet season rainfall. Higher (lower) δ13C values reflect drier (wetter) conditions related to Intertropical Convergence Zone position and trade winds intensity. Comparison with NAO reconstructions (Proctor et al. 2000, Trouet et al. 2009, Wassenburg et al. 2013) reveals that YOK-I δ13C sensitively records NAO-related rainfall dynamics over Belize. The Median Absolute Deviation (MAD) of δ13C extends NAO reconstructions to the last 2,000 years and indicates that high latitude volcanic aerosols force negative NAO phases. We infer that volcanic aerosols modify inter-hemispheric temperature contrasts at multi-annual scale, resulting in meridional relocation of the ITCZ and the Bermuda-Azores High, altering NAO and tropical rainfall patterns. Decade-long dry periods in the 11th and the late 18th century relate to major high northern latitude eruptions and exemplify the climatic response to volcanic forcing by

  1. Review on the Projections of Future Storminess over the North Atlantic European Region

    OpenAIRE

    Tina Mölter; Dirk Schindler; Axel Tim Albrecht; Ulrich Kohnle

    2016-01-01

    This is an overview of the results from previously published climate modeling studies reporting on projected aspects of future storminess over the North Atlantic European region (NAER) in the period 2020–2190. Changes in storminess are summarized for seven subregions in the study area and rated by a categorical evaluation scheme that takes into account emission scenarios and modeling complexity in the reviewed studies. Although many of the reviewed studies reported an increase in the intensit...

  2. Artic-North Atlantic interactions and multidecadal variability of the thermohaline circulation

    OpenAIRE

    Jungclaus, J.; Haak, H.; Latif, Mojib; Mikolajewicz, U.

    2005-01-01

    Analyses of a 500-yr control integration with the non-flux-adjusted coupled atmosphere–sea ice–ocean model ECHAM5/Max-Planck-Institute Ocean Model (MPI-OM) show pronounced multidecadal fluctuations of the Atlantic overturning circulation and the associated meridional heat transport. The period of the oscillations is about 70–80 yr. The low-frequency variability of the meridional overturning circulation (MOC) contributes substantially to sea surface temperature and sea ice fluctuations in the ...

  3. Species Profiles: Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates (South Atlantic): American Eel,

    Science.gov (United States)

    1984-07-01

    freshwater (see the maturation is more rapid in popula- GROWTH CHARACTERISTICS section for , . S tions along the South Atlantic Bight. aging methods ). 4...1.1 mm (Tesch that eels may use geoelectric fields 1977). Incubation periods of American generated by ocean currents to navi- eel eggs are not known...common Robins, C. R., D. M. Cohen, and C. H. methods in eel assessment. Rapp. Robins. 1979. The eels, Anquilla P.-V. Reun. Cons. Int. Explor. and

  4. The Role of Mid-Atlantic Ocean Data Portal in Supporting Ocean Planning

    Directory of Open Access Journals (Sweden)

    Richard G. Lathrop

    2017-08-01

    Full Text Available The Mid-Atlantic Regional Council on the Ocean (MARCO was established in 2009 to enhance the vitality of the region's ocean ecosystem and economy. One of MARCO's first action items was the development of the Mid-Atlantic Ocean Data Portal to serve as an on-line platform to engage stakeholders across the region with the objective of improving their understanding of how ocean resources and places are being used, managed, and conserved. A key component is the Marine Planner, an interactive map-based visualization and decision support tool. These types of on-line tools are becoming increasingly popular means of putting essential data and state-of-the-art visualization technology into the hands of the agencies, industry, community leaders, and stakeholders engaged in ocean planning. However, to be effective, the underlying geospatial data has to be seen as objective, comprehensive, up-to-date and regionally consistent. To meet this challenge, the portal utilizes a distributed network of web map services from credible and authoritative sources. Website analytics and feedback received during the review and comment period of the 2016 release of the Mid-Atlantic Ocean Action Plan confirm that the Data Portal is viewed as integral to this ocean planning process by the MidAtlantic Regional Planning Body and key stakeholders. While not all stakeholders may agree with specific planning decisions, there is broad based agreement on the need for better data and making access to that data widely available.

  5. Second Period Access Report

    DEFF Research Database (Denmark)

    Maisondieu, Christophe; Giebhardt, Jochen; Tetu, Amelie

    The work described in this publication has received support from the European Community - Research Infrastructure Action under the FP7 “Capacities” Specific Programme through grant agreement number 262552, MaRINET. Project Periodic Report. 2nd Period: October 2012 – March 2014 inclusive.......The work described in this publication has received support from the European Community - Research Infrastructure Action under the FP7 “Capacities” Specific Programme through grant agreement number 262552, MaRINET. Project Periodic Report. 2nd Period: October 2012 – March 2014 inclusive....

  6. Painful menstrual periods

    Science.gov (United States)

    Menstruation - painful; Dysmenorrhea; Periods - painful; Cramps - menstrual; Menstrual cramps ... a few days during each menstrual cycle. Painful menstruation is the leading cause of lost time from ...

  7. Solid State compatibilities in CaO-CaO∙Al2O3-CaF2 system

    Directory of Open Access Journals (Sweden)

    Jiménez Molina, S.

    1998-03-01

    Full Text Available In open atmosphere the two phases containing fluorine, C11A7∙CaF2 and 3CA∙CaF2, laying in the CaO-CaO∙Al2O3-CaF2 were synthesized. The synthesis of the 3CA∙CaF2 at 1.100°C was possible without loss of F, when the stoichiometric mixture of CA and CaF2 was pressed into tablets and was applied vacuum, avoiding in such a way the presence of moisture. According to TGA studies, the vapour pressure of phases containing fluorine, at 1.100°C is very low and follows this sequence: CaF2 2 11A7∙CaF2. At 1.000°C the system behaves as condensated. Verification of some compatibilities in solid state in the system CaO-CaO∙Al2O3-CaF2 at 1000°C has been done. Compatibility triangles found are the same described by Chaterjee, and different from the compatibilities given by Brisi and Rolando.Se han sintetizado en atmósfera abierta las dos fases fluoradas del sistema CaO-CaO∙Al2O3-CaF2: C11A7∙CaF2 y 3CA∙CaF2. La síntesis del 3CACaF2 a 1.100°C ha sido posible sin pérdida de F, cuando la mezcla estequiométrica de CA y CaF2 se empastilló a presión y aplicando vacío, como modo de evitar la presencia de humedad. De acuerdo con los resultados de Análisis Termogravimétrico, la presión de vapor de las fases fluoradas, a 1.100°C, es muy baja y sigue el orden: CaF2 2 11A7∙CaF2. A 1.000°C, el sistema se comporta como condensado. Se han verificado algunas relaciones de fases compatibles en estado sólido, en el sistema CaO-CaO∙Al2O3-CaF2, a 1.000°C. Las relaciones de fases compatibles que se han encontrado coinciden con aquéllas descritas por Chaterjee, y son diferentes a las encontradas por Brisi y Rolando.

  8. Transcription factor CREB is involved in CaSR-mediated cytoskeleton gene expression.

    Science.gov (United States)

    Huang, Shuaishuai; Ren, Yu; Wang, Ping; Li, Yanyuan; Wang, Xue; Zhuang, Haihui; Fang, Rong; Wang, Yuduo; Liu, Ningsheng; Hehir, Michael; Zhou, Jeff X

    2015-03-01

    Our previous studies illustrated that a steady increase of intracellular calcium concentration ([Ca2+]i) was important for maintaining microtubules (MTs) rearrangement in apoptotic cells. However, little is known about the effect of calcium sensing receptor (CaSR)-mediated increase in [Ca2+]i on cytoskeleton gene expression. We examined the impact of taxol or CaSR agonist/antagonist on the regulation of [Ca2+]i concentration, cytoskeleton arrangement, phosphorylated CREB and cytoskeleton gene expressions in HeLa cells with dominant negative plasmid of CREB (PM). This study demonstrated that Gdcl3 (a specific CaSR agonist) evoked a rapid increase of [Ca2+]i, formed a rigid bundle of MTs which surrounded the nucleus and decreased the cytoskeleton gene expressions in HeLa cells. These effects were rescued by addition of NPS2390 (a specific CaSR antagonist). Moreover, CaSR activity affected cytoskeleton gene expression through transcription factor CREB. Histoscores of pCREB immunoreactivity in tissues of cervical adenocarcinoma, renal clear cell carcinoma, and diffuse large B-cell lymphoma were markedly increased compared with non malignant tissue. These data demonstrate, for the first time, that CaSR-mediated increase in [Ca2+]i probably modulate cytoskeleton organization and gene expression via transcription factor. © 2014 Wiley Periodicals, Inc.

  9. Ocean circulation, ice sheet growth and interhemispheric coupling of millennial climate variability during the mid-Pleistocene (ca 800-400 ka)

    Science.gov (United States)

    Alonso-Garcia, M.; Sierro, F. J.; Kucera, M.; Flores, J. A.; Cacho, I.; Andersen, N.

    2011-11-01

    Stable carbon and oxygen isotopes from benthic and planktic foraminifers, planktic foraminifer assemblages and ice rafted debris from the North Atlantic Site U1314 (Integrated Ocean Drilling Program Expedition 306) were examined to investigate orbital and millennial-scale climate variability in the North Atlantic and its impact on global circulation focusing on the development of glacial periods during the mid-Pleistocene (ca 800-400 ka). Glacial initiations were characterized by a rapid cooling (6-10 °C in less than 7 kyr) in the mean annual sea surface temperature (SST), increasing benthic δ 18O values and high benthic δ 13C values. The continuous increase in benthic δ 18O suggests a continuous ice sheet growth whereas the positive benthic δ 13C values indicate that the flow of the Iceland Scotland Overflow water (ISOW) was vigorous. Strong deep water formation in the Norwegian Greenland Sea promoted a high transfer of freshwater from the ocean to the continents. However, low SSTs at Site U1314 suggest a subpolar gyre cooling and freshening that may have reduced deep water formation in the Labrador Sea during glacial initiations. Once the 3.5‰ threshold in the benthic δ 18O record was exceeded, ice rafting started and ice sheet growth was punctuated by millennial-scale waning events which returned to the ocean part of the freshwater accumulated on the continents. Ice-rafting events were associated with a rapid reduction in the ISOW (benthic δ 13C values dropped 0.5-1‰) and followed by millennial-scale warmings. The first two millennial-scale warm intervals of each glacial period reached interglacial temperatures and were particularly abrupt (6-10 °C in ˜3 kyr). Subsequent millennial-scale warm events were cooler probably because the AMOC was rather reduced as suggested by the low benthic δ 13C values. These two abrupt warming events that occurred at early glacial periods were also observed in the Antarctic temperature and CO 2 records, suggesting a

  10. 75 FR 35767 - Fisheries of the South Atlantic; South Atlantic Fishery Management Council; Public Meeting

    Science.gov (United States)

    2010-06-23

    ... (SERMA) in the South Atlantic, and receive updates on state enforcement efforts of 2010 snapper grouper... ] Conservation Biology Institute (MCBI) which addresses the challenges of enforcing regulations within the vast...

  11. 78 FR 4129 - Fisheries of the South Atlantic; South Atlantic Fishery Management Council; Public Meetings

    Science.gov (United States)

    2013-01-18

    .... Receive an update on the Atlantic States Marine Fisheries Communication Group Social Media Workshop. 3.... Review Joint Mackerel Amendment 19, which addresses bag limit sales of king mackerel, Spanish mackerel...

  12. Persistent influence of tropical North Atlantic wintertime sea surface temperature on the subsequent Atlantic hurricane season

    Science.gov (United States)

    Wang, Xidong; Liu, Hailong; Foltz, Gregory R.

    2017-08-01

    This study explores the seasonally lagged impact of wintertime sea surface temperature (SST) in the Atlantic main development region (MDR) on the subsequent Atlantic hurricane season. It is found that wintertime SST anomalies in the MDR can persist into the summer, explaining 42% of the variance in the subsequent hurricane season's SST during 1951-2010. An anomalously warm wintertime in the MDR is usually followed by an anomalously active hurricane season. Analysis shows an important constraint on the seasonal evolution of the MDR SST by the water vapor feedback process, in addition to the well-known wind-evaporation-SST and cloud-SST feedback mechanisms over the tropical North Atlantic. The water vapor feedback influences the seasonal evolution of MDR SST by modulating seasonal variations of downward longwave radiation. This wintertime thermal control of hurricane activity has significant implications for seasonal predictions and long-term projections of hurricane activity over the North Atlantic.

  13. 76 FR 23935 - Atlantic Highly Migratory Species; Atlantic Shark Management Measures

    Science.gov (United States)

    2011-04-29

    ... Species; Atlantic Shark Management Measures AGENCY: National Marine Fisheries Service (NMFS), National..., or selling of hammerhead sharks in the family Sphyrnidae (except for Sphyrna tiburo) and oceanic whitetip sharks (Carcharhinus longimanus) caught in association with ICCAT fisheries. This rule would...

  14. 76 FR 62331 - Atlantic Highly Migratory Species; Atlantic Shark Management Measures

    Science.gov (United States)

    2011-10-07

    ... Species; Atlantic Shark Management Measures AGENCY: National Marine Fisheries Service (NMFS), National... blacknose sharks, NMFS is declaring the following stock status determinations. Sandbar sharks are still overfished, but no longer experiencing overfishing. Dusky sharks are still overfished and still experiencing...

  15. New records of Pennatulacea (Anthozoa: Octocorallia from the African Atlantic coast, with description of a new species and a zoogeographic analysis

    Directory of Open Access Journals (Sweden)

    Pablo J. López-González

    2001-03-01

    Full Text Available A collection of pennatulaceans from ten cruises, acquired between 1982 and 1989 from off the western African coast comprises ca. 350 specimens of 13 species. One of the cruise is from the Gulf of Guinea and eight from the Southeast Atlantic. Fifty-four stations were sampled from depths of 91-1112 m. One previously undescribed species in the genus Stylatula is reported and described as new from samples collected from the Namibian continental shelf. Considering these collections, and previous records, the pennatulaceans in the western African region show biogeographic affinities with three geographic areas: West Africa (55.5% of the species, which comprises the Canary, Gulf of Guinea, and Benguela regions; the North Atlantic (3.7% of the species, which represents the more widespread Atlantic taxa; and Cape Endemic (7.4% of the species, which comprises the southern African region.

  16. Exploring Climate-Smart Land Management for Atlantic Europe

    Directory of Open Access Journals (Sweden)

    Rogier P. O. Schulte

    2016-09-01

    Full Text Available Soils can be a sink or source of carbon, and managing soil carbon has significant potential to partially offset agricultural greenhouse gas emissions. While European Union (EU member states have not been permitted to account for this offsetting potential in their efforts to meet the EU 2020 reduction targets, this policy is now changing for the period 2020 to 2030, creating a demand for land management plans aimed at maximizing the offsetting potential of land. In this letter, we derive a framework for climate-smart land management in the Atlantic climate zone of the EU by combining the results from five component research studies on various aspects of the carbon cycle. We show that the options for proactive management of soil organic carbon differ according to soil type and that a spatially tailored approach to land management will be more effective than blanket policies.

  17. Amplification of the Atlantic Multidecadal Oscillation associated with the onset of the industrial-era warming

    Science.gov (United States)

    Moore, Kent; Majeed, Haris; Halfar, Jochen; Adey, Walter; Kronz, Andreas

    2017-04-01

    North Atlantic sea surface temperatures experience variability with a periodicity of 60-80 years that is known as the Atlantic Multidecadal Oscillation (AMO). It has a profound imprint on the global climate system that results in a number of high value societal impacts. However the industrial period, i.e. the middle of the 19th century onwards, contains only two full cycles of the AMO making it difficult to fully characterize this oscillation and its impact on the climate system. As a result, there is a clear need to identify paleoclimate records extending into the pre-industrial period that contain an expression of the AMO. This is especially true for extratropical marine paleoclimate proxies where such expressions are currently unavailable. Here we present an annually resolved coralline algal time series from the northwest Atlantic Ocean that exhibits multidecadal variability extending back six centuries. The time series contains a statistically significant trend towards higher values, i.e. warmer conditions, beginning in the 19th century that coincided with an increase in the time series' multidecadal power. We argue that these changes are associated with a regional climate reorganization involving an amplification of the AMO that coincided with onset of the industrial-era warming.

  18. KWU-werkersklasdramas in Afrikaans (ca. 1930 - ca. 1950

    Directory of Open Access Journals (Sweden)

    J. L. Coetser

    1999-05-01

    Full Text Available GWU working class theatre in Afrikaans (ca. 1930 - ca. 1950In 1984 Elsabé Brink drew attention to plays, prose and poetry written between 1930 and 1950 in Afrikaans by members of the Garment Workers’ Union (GWU. Scholars such as Stander and Willemse (1992, Van Niekerk (1996 and Van Wyk (1995, 1997 have also referred to GWU plays. Apart from these overviews, GWU plays as such have not yet received the attention they deserve. This article presents a revaluation, initially by providing an overview of their contents, followed by an examination of cultural, economic and political influences. It is argued that - retrospectively - the GWU plays reflected a unique cultural specificity from the framework established by Sitas (1986 for more contemporary working class theatre.

  19. Population genetic structure of the abyssal grenadier (Coryphaenoides armatus) around the mid-Atlantic ridge

    Science.gov (United States)

    Ritchie, H.; Cousins, N. J.; Cregeen, S. J.; Piertney, S. B.

    2013-12-01

    Understanding the factors that affect the levels and distribution of genetic diversity in oceanic and deep sea environments is a central focus in marine population genetics. Whilst it has been considered that the oceans represent a homogenous environment that would facilitate dispersal and minimise population structure, it is now clear that topographical features and current patterns can influence the extent of spatial gene flow and promote significant population genetic divergence even at local scales. Here we examine patterns of population genetic structure among N. Atlantic populations of the cosmopolitan abyssal grenadier Coryphaenoides armatus in relation to two hypothesised barriers to gene flow-the mid-Atlantic Ridge and the Charlie-Gibbs Fracture Zone/Sub-Polar Front. A suite of microsatellite markers were developed to examine the spatial pattern of allelic variation among 210 individuals from ten sampling locations encompassing sites east and west of the MAR and north and south of the CGFZ, plus a geographically distinct sample of individuals from the Crozet Islands in the Indian Ocean. Considerable genetic diversity was detected among individuals (na=5-13 and HO=0.46-0.69 across populations) but with an overall lack of genetic divergence between populations. Pairwise estimates of divergence among NE Atlantic samples were small and non-significant (max FST=0.04) and Structure-based Bayesian analysis of genetic clusters returned no distinct population structure. The only indication of genetic structure was between the Atlantic and Indian Oceans, with FST estimates of ca. 0.05. Patterns of genetic diversity and divergence are discussed in relation to what has been resolved in Coryphaenoides congeners, and what is known about the life history and ecology of C. armatus.

  20. Seasonality in the Western Mediterranean During the Last Glacial From Paired Oxygen Isotopes and Mg/Ca in Limpet Shells

    Science.gov (United States)

    Ferguson, J. E.; Henderson, G. M.; Fa, D.; Finlayson, C.

    2008-12-01

    Molluscs have shown great potential to act as seasonal-resolution archives of sea-surface temperatures (SST) at mid to high latitudes, outside the range of tropical surface corals. Seasonal resolution climate records from higher latitudes are important to allow investigation of the role of seasonality in controlling mean climate on diverse timescales, and of the evolution of climate systems such as the North Atlantic Oscillation. Long sequences of intertidal mollusc shells are difficult to find due to sea level fluctuations over glacial- interglacial periods. This study makes use of Patella shells collected by Neanderthals and humans and transported inland to caves on Gibraltar over at least the last 120 kyrs. Some 30 fossil Patella shells were selected from several hundred excavated from Gorham's and Vanguard Caves at Gibraltar. Oxygen isotope analysis of micromilled samples of modern Patella shells from the Gibraltar coastline demonstrate that the shells accurately record absolute SSTs and capture more than 80% of the full seasonal range. Analysis of fossil Patella shells, dated using 14C, provides records of the change in absolute SST and seasonality during the last glacial. Paired Mg/Ca ratios of micromilled samples in modern Patella shells follow a consistent positive relationship with SST providing an independent paleothermometer, analogous with coral Sr/Ca. Applying this Mg/Ca-SST relationship to fossil Patella shells allows the independent reconstruction of the absolute values and range of SSTs and the reconstruction of seawater δ18O for the western Mediterranean. Results show a cooling of glacial summer SSTs from 36 kyr BP to the LGM with maximum cooling of glacial summer SSTs of 7.5 °C relative to modern. In contrast, winter SSTs show greater variability on millennial timescales with a maximum cooling of up to 10 °C. SST seasonality is therefore extended due to greater winter cooling but SST seasonality is highly variable as a result of large

  1. The Living Periodic Table

    Science.gov (United States)

    Nahlik, Mary Schrodt

    2005-01-01

    To help make the abstract world of chemistry more concrete eighth-grade students, the author has them create a living periodic table that can be displayed in the classroom or hallway. This display includes information about the elements arranged in the traditional periodic table format, but also includes visual real-world representations of the…

  2. Glacial climate sensitivity to different states of the Atlantic Meridional Overturning Circulation: results from the IPSL model

    Directory of Open Access Journals (Sweden)

    M. Kageyama

    2009-09-01

    Full Text Available Paleorecords from distant locations on the globe show rapid and large amplitude climate variations during the last glacial period. Here we study the global climatic response to different states of the Atlantic Meridional Overturning Circulation (AMOC as a potential explanation for these climate variations and their possible connections. We analyse three glacial simulations obtained with an atmosphere-ocean coupled general circulation model and characterised by different AMOC strengths (18, 15 and 2 Sv resulting from successive ~0.1 Sv freshwater perturbations in the North Atlantic. These AMOC states suggest the existence of a freshwater threshold for which the AMOC collapses. A weak (18 to 15 Sv AMOC decrease results in a North Atlantic and European cooling. This cooling is not homogeneous, with even a slight warming over the Norwegian Sea. Convection in this area is active in both experiments, but surprisingly stronger in the 15 Sv simulation, which appears to be related to interactions with the atmospheric circulation and sea-ice cover. Far from the North Atlantic, the climatic response is not significant. The climate differences for an AMOC collapse (15 to 2 Sv are much larger and of global extent. The timing of the climate response to this AMOC collapse suggests teleconnection mechanisms. Our analyses focus on the North Atlantic and surrounding regions, the tropical Atlantic and the Indian monsoon region. The North Atlantic cooling associated with the AMOC collapse induces a cyclonic atmospheric circulation anomaly centred over this region, which modulates the eastward advection of cold air over the Eurasian continent. This can explain why the cooling is not as strong over western Europe as over the North Atlantic. In the Tropics, the southward shift of the Inter-Tropical Convergence Zone appears to be strongest over the Atlantic and Eastern Pacific and results from an adjustment of the atmospheric and oceanic heat transports. Finally, the

  3. On some periodicity effects

    DEFF Research Database (Denmark)

    Sorokin, Sergey V.

    2015-01-01

    The talk is concerned with the modelling of wave propagation in and vibration of periodic elastic structures. Although analysis of wave-guide properties of infinite periodic structures is a well establish research subject, some issues have not yet been fully addressed in the literature. The aim...... of the talk is to illustrate these issues in simple examples and to discuss possible applications and generalisations. First, the eigenfrequency spectra of finite periodic structures are compared with the location of stop-bands for their infinite counterparts for a hierarchy of four mathematical models....... In each case, special attention is paid to eigenfrequencies and eigenmodes of a single periodicity cell with appropriate boundary conditions. The influence of the amount of periodicity cells in a finite compound structure on its eigenfrequency spectrum is analyzed. Several features common...

  4. Periods and Nori motives

    CERN Document Server

    Huber, Annette

    2017-01-01

    This book casts the theory of periods of algebraic varieties in the natural setting of Madhav Nori’s abelian category of mixed motives. It develops Nori’s approach to mixed motives from scratch, thereby filling an important gap in the literature, and then explains the connection of mixed motives to periods, including a detailed account of the theory of period numbers in the sense of Kontsevich-Zagier and their structural properties. Period numbers are central to number theory and algebraic geometry, and also play an important role in other fields such as mathematical physics. There are long-standing conjectures about their transcendence properties, best understood in the language of cohomology of algebraic varieties or, more generally, motives. Readers of this book will discover that Nori’s unconditional construction of an abelian category of motives (over fields embeddable into the complex numbers) is particularly well suited for this purpose. Notably, Kontsevich's formal period algebra represents a to...

  5. North Atlantic storm track response to decadal fluctuations of the Atlantic Meridional Overturning Circulation (AMOC)

    Science.gov (United States)

    Frankignoul, C.; Msadek, R.; Li, L.

    2009-12-01

    The mechanisms of the atmospheric circulation response to a sea surface temperature (SST) anomaly induced by decadal fluctuations of the Atlantic Meridional Overturning Circulation (AMOC) in a climate model is investigated using prescribed change experiments with its atmospheric component coupled to a slab ocean. The prescribed SST anomaly in the North Atlantic is the surface signature of the AMOC influence on the atmosphere detected in the coupled simulation. It follows the AMOC by a few years and resembles the model Atlantic Multidecadal Oscillation (AMO). A diagnostic analysis with daily data emphasizes the role of transient-eddy forcing in shaping and maintaining the equilibrium response. We show that in response to an intensified AMOC, the North Atlantic storm tracks are enhanced and shifted northward during summer, consistently with a strengthening of the westerlies. The winter response to the AMOC-induced North Atlantic warming is an intensification of the subtropical jet and a southward shift of the Atlantic storm track activity, resulting in an equatorward shift of the polar jet. The atmospheric response is highly non linear in both seasons as the result of a strong interaction between transient eddies and the mean flow. This study emphasizes that decadal fluctuations of the AMOC can affect the storm tracks location and intensity, both in winter and summer, leading to significant dynamical changes in the atmosphere associated with global climate impacts.

  6. Opportunity potential matrix for Atlantic Canadians

    Science.gov (United States)

    Greg Danchuk; Ed Thomson

    1992-01-01

    Opportunity for provision of Parks Service benefit to Atlantic Canadians was investigated by mapping travel behaviour into a matrix in terms of origin, season, purpose, distance, time, and destination. Findings identified potential for benefit in several activity areas, particularly within residents' own province.

  7. Population structure of Atlantic Mackerel (Scomber scombrus)

    DEFF Research Database (Denmark)

    Jansen, Teunis; Gislason, Henrik

    2013-01-01

    model where the population structure of mackerel is described as a dynamic cline, rather than as connected contingents. Temporal changes in hydrography and mackerel behavior may affect the steepness of the cline at various locations. The new interpretation of the population structure of Atlantic...

  8. Subpolar North Atlantic glider observations for OSNAP

    Science.gov (United States)

    Zhou, C.; Hodges, B.; Bower, A. S.; Yang, J.; Lin, X.

    2016-02-01

    OSNAP is an international program designed to provide a continuous record of the full-water-column, trans-basin fluxes of heat, mass, and freshwater in the subpolar North Atlantic. The observational efforts of this program are focused largely along lines connecting Labrador to Greenland, and Greenland to Scotland. The OSNAP experimental plan includes continuous sampling by Slocum G2 gliders along the latter (easternmost) of these two sections, specifically across the northeastward-flowing North Atlantic Current in the Iceland Basin. The glider observations, a collaboration between the Ocean University of China and Woods Hole Oceanographic Institution, provide higher spatial resolution of water properties than is possible from moorings alone. These observations commenced in June 2015 with a mission to fly back and forth along a section between two OSNAP moorings, profiling from the surface to 1000-m depth. As of September 2015, five sections (including over 240 profiles) have been recorded. As expected, the data indicates energetic intraseasonal variability at smaller scales than can be captured by the OSNAP mooring array. We are investigating how this variability may impact calculated fluxes of heat, mass, and freshwater. The glider repeatedly crossed a cyclonic eddy between the two moorings, enabling study of fine thermohaline structure during the development and dissipation of mesoscale eddies in the subpolar North Atlantic. With additional sensors measuring fluorescence, dissolved oxygen, nitrate, and multispectral light, the dataset also has the potential to significantly advance our understanding of the biogeochemical processes of mesoscale and submesoscale eddies in the subpolar North Atlantic.

  9. Origins of the North Atlantic Treaty.

    Science.gov (United States)

    Rotter, Andrew J.

    1983-01-01

    The author is persuaded that the main purpose of the North Atlantic Treaty Organization (NATO) was to raise the confidence of moderate ruling groups in Western Europe. Today NATO is an expression of support between troubled allies with a number of common interests. (RM)

  10. The North Atlantic Treaty Organization at 40.

    Science.gov (United States)

    Baker, John A.

    1989-01-01

    Surveys the history of the North Atlantic Treaty Organization's (NATO) on the 40th anniversary of the signing of the Treaty. Highlights milestones in the Organization's history of dealing with the Soviet Union, from containment to the Intermediate-Range Nuclear Forces Treaty. Discusses needs, tasks, and challenges that NATO faces in the 1990s.…

  11. Coccolithophores in the equatorial Atlantic Ocean

    DEFF Research Database (Denmark)

    Kinkel, Hanno; Baumann, K.-H.; Cepek, M.

    2000-01-01

    The present study was initiated to ascertain the significance of coccolithophores as a proxy for paleoceanographic and paleoproductivity studies in the equatorial Atlantic. Data from a range of different samples, from the plankton, surface sediments as well as sediment cores are shown and compare...

  12. Predicting multiyear North Atlantic Ocean variability

    NARCIS (Netherlands)

    Hazeleger, W.; Wouters, B.; Oldenborgh, van G.J.; Corti, S.; Palmer, T.; Lloyd Smith, D.; Dunstone, N.; Kroger, J.; Pohlmann, H.; Storch, von J.S.

    2013-01-01

    We assess the skill of retrospective multiyear forecasts of North Atlantic ocean characteristics obtained with ocean-atmosphere-sea ice models that are initialized with estimates from the observed ocean state. We show that these multimodel forecasts can skilfully predict surface and subsurface ocean

  13. Photometric and spectroscopic monitoring of AA Tau, DN Tau, UX Tau A, T Tau, RY Tau, Lk Ca 4, and Lk Ca 7

    Science.gov (United States)

    Vrba, F. J.; Chugainov, P. F.; Weaver, W. B.; Stauffer, J. S.

    1993-01-01

    We report the results of a UBVRI photometric monitoring campaign for three classical T Tauri stars (AA Tau, DN Tau, and UX Tau A) and two weak emission line T Tauri stars (Lk Ca 4 and Lk Ca 7). Observations were obtained at three sites during a core observing period spanning UT 1985 October 14 through UT 1985 December 25, with additional observations continuing until UT 1986 April 6. Concurrent spectrophotometric observations were obtained for all main program stars except Lk Ca 7 and additionally for T Tau, RW Aur, and RY Tau. Periodic photometric variability, assumed to be the stars' rotation periods, were found for AA Tau, DN Tau, Lk Ca 4, and Lk Ca 7, respectively, as 8.2, 6.3, 3.4, and 5.7 days. Several U-filter flares were observed for Lk Ca 4 and Lk Ca 7, which are strongly concentrated toward phases of minimum light. Correlations are found between H-alpha line strengths and V magnitudes for AA Tau and RY Tau. An analysis of absolute color variations of classical T Tauri stars confirms that hot spots are the predominant cause of these stars' variability. Our overall results are consistent with earlier findings that long-lived cool spots are responsible for most of the variability found for weak-emission T Tauri stars, while temporal hot spots are primarily responsible for the observed variability found in classical T Tauri stars.

  14. Twentieth century warming of the tropical Atlantic captured by Sr-U paleothermometry

    Science.gov (United States)

    Alpert, Alice E.; Cohen, Anne L.; Oppo, Delia W.; DeCarlo, Thomas M.; Gaetani, Glenn A.; Hernandez-Delgado, Edwin A.; Winter, Amos; Gonneea, Meagan

    2017-01-01

    Coral skeletons are valuable archives of past ocean conditions. However, interpretation of coral paleotemperature records is confounded by uncertainties associated with single-element ratio thermometers, including Sr/Ca. A new approach, Sr-U, uses U/Ca to constrain the influence of Rayleigh fractionation on Sr/Ca. Here we build on the initial Pacific Porites Sr-U calibration to include multiple Atlantic and Pacific coral genera from multiple coral reef locations spanning a temperature range of 23.15–30.12°C. Accounting for the wintertime growth cessation of one Bermuda coral, we show that Sr-U is strongly correlated with the average water temperature at each location (r2 = 0.91, P Mean Sr-U temperatures and patterns of multiyear variability were replicated in a second coral in the same grid box. Conversely, Sr/Ca records from the same two corals were inconsistent with each other and failed to capture absolute sea temperatures, timing of multiyear variability, or the twentieth century warming trend. Our results suggest that coral Sr-U paleothermometry is a promising new tool for reconstruction of past ocean temperatures.

  15. AtlantOS - Optimizing and Enhancing the Integrated Atlantic Ocean Observing System

    Science.gov (United States)

    Reitz, Anja; Visbeck, Martin; AtlantOS Consortium, the

    2016-04-01

    Atlantic Ocean observation is currently undertaken through loosely-coordinated, in-situ observing networks, satellite observations and data management arrangements of heterogeneous international, national and regional design to support science and a wide range of information products. Thus there is tremendous opportunity to develop the systems towards a fully integrated Atlantic Ocean Observing System consistent with the recently developed 'Framework of Ocean Observing'. The vision of AtlantOS is to improve and innovate Atlantic observing by using the Framework of Ocean Observing to obtain an international, more sustainable, more efficient, more integrated, and fit-for-purpose system. Hence, the AtlantOS initiative will have a long-lasting and sustainable contribution to the societal, economic and scientific benefit arising from this integrated approach. This will be delivered by improving the value for money, extent, completeness, quality and ease of access to Atlantic Ocean data required by industries, product supplying agencies, scientist and citizens. The overarching target of the AtlantOS initiative is to deliver an advanced framework for the development of an integrated Atlantic Ocean Observing System that goes beyond the state-of -the-art, and leaves a legacy of sustainability after the life of the project. The legacy will derive from the following aims: i) to improve international collaboration in the design, implementation and benefit sharing of ocean observing, ii) to promote engagement and innovation in all aspects of ocean observing, iii) to facilitate free and open access to ocean data and information, iv) to enable and disseminate methods of achieving quality and authority of ocean information, v) to strengthen the Global Ocean Observing System (GOOS) and to sustain observing systems that are critical for the Copernicus Marine Environment Monitoring Service and its applications and vi) to contribute to the aims of the Galway Statement on Atlantic

  16. Reconstruction of the North Atlantic tropical cyclones in Azores for the last 800 years.

    Science.gov (United States)

    Rubio-Ingles, Maria Jesus; Sánchez, Guiomar; Trigo, Ricardo; Francus, Pierre; Gonçalves, Vitor; Raposeiro, Pedro; Freitas, Conceiçao; Borges, Paolo; Hernández, Armand; Bao, Roberto; Vázquez-Loureiro, David; Andrade, Cesar; Sáez, Alberto; Giralt, Santiago

    2014-05-01

    .5 m long core allowed us to recover the whole sedimentary infill of Azul Lake, which has been characterized using a multiproxy (geochemistry, diatoms and chironomid head capsules) approach. The last 800 cal years BP, dated by the use of 14C (plant remains) and 210Pb, have been recorded in the 1.5 m of sediment. The layers of flood events deposits are characterized by low Ti content, no diatoms, and both high organic content and terrestrial plants remains. 14C and 210Pb dates obtained in this core have been used to link the flood events recorded in the offshore zones of the lake with the historical storms hitting the archipelago. According to the results of the studied sediment core, the number of tropical storms hitting the island has increased for the last 50 years. This is in accordance with the findings done by other authors (Liu et al., 2001 and Besonen et al., 2008). Moreover, two other periods located around the 1450s and the 1650s also recorded high number of storms. An increase of typhoons in China and hurricanes reaching the north Atlantic coast of United States during the same periods suggests a global climate pattern that ruled these extreme phenomena. LITERATURE: Andrade, C., Trigo R.M., Freitas, M.C., Gallego M.C., Borges, P., Ramos, A.M. (2008) "Comparing Historic Records of Storm frequency and the North Atlantic Oscillation (NAO) chronology for the Azores region", The Holocene, 18, 745-754 Besonen M.R., Bradley S.B., Mudelsee M., Abbott M.B, Francus P. (2008) "A 1000-year, annually-resolved record of hurricane activity from Boston, Massachussets" Geophysical Research Letters. Vol.35, L14705. Liu, K.-b., Shen, C. and Louie, K.-s. (2001), A 1,000-Year History of Typhoon Landfalls in Guangdong, Southern China, Reconstructed from Chinese Historical Documentary Records. Annals of the Association of American Geographers, 91: 453-464. doi: 10.1111/0004-5608.00253

  17. Population structure of Atlantic mackerel (Scomber scombrus.

    Directory of Open Access Journals (Sweden)

    Teunis Jansen

    Full Text Available Atlantic mackerel (Scomber scombrus occurs on both sides of the north Atlantic and has traditionally been grouped into 5 spawning components, some of which were thought to be isolated natal homing stocks. Previous studies have provided no evidence for cross Atlantic migration and no or weak support for isolated spawning components within either side of the North Atlantic. We question the de-facto accepted hypothesis of isolation between spawning components on the basis of spawning and age distribution data. The spawning intensities, proxied by larval abundances, are negatively correlated between the North Sea and Celtic Sea, which indicates that the two spawning components may be connected by straying individuals. This finding is based on unique larvae samples collected before the collapse of North Sea component, thus showing that the exchange is not a recent phenomenon due to the collapse. The analyses of old as well as more recent age distributions show that strong year classes spread into other areas where they spawn as adults ("twinning". Our findings are in accordance with the lack of solid evidence for stock separation from previous analyses of tagging data, genetics, ectoparasite infections, otolith shapes, and blood phenotypes. Because no method has been able to identify the origin of spawning mackerel unequivocally from any of the traditional spawning components, and in the light of our results, we conclude that straying outweighs spatial segregation. We propose a new model where the population structure of mackerel is described as a dynamic cline, rather than as connected contingents. Temporal changes in hydrography and mackerel behavior may affect the steepness of the cline at various locations. The new interpretation of the population structure of Atlantic mackerel has important implications for research, assessment and management.

  18. Atlantic Meridional Overturning Circulation response to idealized external forcing

    Energy Technology Data Exchange (ETDEWEB)

    Park, W.; Latif, M. [Leibniz-Institut fuer Meereswissenschaften an der Universitaet Kiel, Kiel (Germany)

    2012-10-15

    The response of the Atlantic Meridional Overturning Circulation (AMOC) to idealized external (solar) forcing is studied in terms of the internal (unforced) AMOC modes with the Kiel Climate Model (KCM), a coupled atmosphere-ocean-sea ice general circulation model. The statistical investigation of KCM's internal AMOC variability obtained from a multi-millennial control run yields three distinct modes: a multi-decadal mode with a period of about 60 years, a quasi-centennial mode with a period of about 100 years and a multi-centennial mode with a period of about 300-400 years. Most variance is explained by the multi-centennial mode, and the least by the quasi-centennial mode. The solar constant varies sinusoidally with two different periods (100 and 60 years) in forced runs with KCM. The AMOC response to the external forcing is rather complex and nonlinear. It involves strong changes in the frequency structure of the variability. While the control run depicts multi-timescale behavior, the AMOC variability in the experiment with 100 year forcing period is channeled into a relatively narrow band centered near the forcing period. It is the quasi-centennial AMOC mode with a period of just under 100 years which is excited, although it is heavily damped in the control run. Thus, the quasi-centennial mode retains its period which does not correspond exactly to the forcing period. Surprisingly, the quasi-centennial mode is also most strongly excited when the forcing period is set to 60 years, the period of the multi-decadal mode which is rather prominent in the control run. It is largely the spatial structure of the forcing rather than its period that determines which of the three internal AMOC modes is excited. The results suggest that we need to understand the full modal structure of the internal AMOC variability in order to understand the circulation's response to external forcing. This could be a challenge for climate models: we cannot necessarily expect that the

  19. Mean-periodic functions

    Directory of Open Access Journals (Sweden)

    Carlos A. Berenstein

    1980-01-01

    Full Text Available We show that any mean-periodic function f can be represented in terms of exponential-polynomial solutions of the same convolution equation f satisfies, i.e., u∗f=0(μ∈E′(ℝn. This extends to n-variables the work of L. Schwartz on mean-periodicity and also extends L. Ehrenpreis' work on partial differential equations with constant coefficients to arbitrary convolutors. We also answer a number of open questions about mean-periodic functions of one variable. The basic ingredient is our work on interpolation by entire functions in one and several complex variables.

  20. The Effects of Temperature, Hypoxia and Hypercapnia on the Metabolism of Atlantic Cod Gadus morhua

    DEFF Research Database (Denmark)

    Tirsgård, Bjørn

    showed that RMRlow and RMRhigh increased with age, by scaling exponents ranging between 0.58 and 0.87 at the three temperature tested. In periods with low prey availability a low water temperature and body size increase the survival rate whereas high water temperatures enhance growth rate when prey......The Atlantic cod (Gadus morhua L. 1758) is an important species both as a major top predator in the ecosystem and economical marine resource in the fishing industry of Northern Europe (Andersen, 2012). As an ectothermic water breather the Atlantic cod is continuously exposed to annual changes...... in the water conditions affecting their performance, growth and reproduction. Variations in the water conditions between years and due to climatic changes, affects the survival rate, population dynamic and bio-energetic distribution of the Atlantic cod (Hansson et al., 1996; Essington et al., 2001...

  1. Review of the late-Holocene storm events along the European Atlantic coasts

    Science.gov (United States)

    Pouzet, Pierre; Maanan, Mohamed; Piotrowska, Natalia; Baltzer, Agnès; Stephan, Pierre

    2017-04-01

    The chronology of the mid- to late-Holocene coastal storms was reconstructed from vibracore samplings, 14C dating and sedimentary analysis from Yeu island (French Atlantic coast). The methodology used is based on the identification of disturbing sedimentary events recognized within three Holocene sedimentary transgressive sequences selected along the northern coast of the island. These sequences correspond to the present-day coastal salt-marshes and swamps. The sediment cores were centimeter-sampled and studied from several sedimentological proxies (Loss of Ignition, sand fraction, mean grain size) with a high temporal resolution. Chronology was built by age-depth model based on eleven 14C measures of organic sediments and shell samples. Ten paleo-storm events were recorded: a 2100-1950 calBP interval as a deeply stormy-disturbed period; five others major impacted times: 600-500 calBP, 2850-2350 calBP, 3500-3270 calBP, 5400-5370 calBP and 6650-6510 calBP; and four final less meaningful storminess hypothesis near 1590 calBP, 6000 calBP, 7000 calBP, and between 7670 and 7470 calBP. This chronology was compared with enhanced storminess periods recognized along the European Atlantic coast. Four stormy periods stand out from the last 4000 years: 600-300 BP, 1100-1700 BP, 2500-2900 BP and 3300-3500 BP, corresponding to late Holocene global cold events. These results suggests that these changes in coastal hydrodynamics were in phase with those identified over the North-eastern Atlantic and seem to correspond to Holocene cooling first shown in the North Atlantic and associated with decreases in sea surface temperature.

  2. Some physical drivers of changes in the winter storm tracks over the North Atlantic and Mediterranean during the Holocene.

    Science.gov (United States)

    Brayshaw, David James; Hoskins, Brian; Black, Emily

    2010-11-28

    The winter climate of Europe and the Mediterranean is dominated by the weather systems of the mid-latitude storm tracks. The behaviour of the storm tracks is highly variable, particularly in the eastern North Atlantic, and has a profound impact on the hydroclimate of the Mediterranean region. A deeper understanding of the storm tracks and the factors that drive them is therefore crucial for interpreting past changes in Mediterranean climate and the civilizations it has supported over the last 12 000 years (broadly the Holocene period). This paper presents a discussion of how changes in climate forcing (e.g. orbital variations, greenhouse gases, ice sheet cover) may have impacted on the 'basic ingredients' controlling the mid-latitude storm tracks over the North Atlantic and the Mediterranean on intermillennial time scales. Idealized simulations using the HadAM3 atmospheric general circulation model (GCM) are used to explore the basic processes, while a series of timeslice simulations from a similar atmospheric GCM coupled to a thermodynamic slab ocean (HadSM3) are examined to identify the impact these drivers have on the storm track during the Holocene. The results suggest that the North Atlantic storm track has moved northward and strengthened with time since the Early to Mid-Holocene. In contrast, the Mediterranean storm track may have weakened over the same period. It is, however, emphasized that much remains still to be understood about the evolution of the North Atlantic and Mediterranean storm tracks during the Holocene period.

  3. Fingerprinting Northeast Atlantic water masses using neodymium isotopes

    Science.gov (United States)

    Dubois-Dauphin, Quentin; Colin, Christophe; Bonneau, Lucile; Montagna, Paolo; Wu, Qiong; Van Rooij, David; Reverdin, Gilles; Douville, Eric; Thil, François; Waldner, Astrid; Frank, Norbert

    2017-08-01

    -depth (<-13.5 ± 0.3) indicate that the MSW has no influence, even during periods of low NAO index. Water masses deeper than 1200 m in the northeast Atlantic are clearly influenced by the less radiogenic Labrador Sea Water (LSW) (εNd between -13.4 ± 0.3 and -14.0 ± 0.3) that mixes locally in the Iceland basin with the Iceland-Scotland Overflow Water (ISOW) (between -10.3 ± 0.2 and -11.3 ± 0.3).

  4. A geological perspective on the degradation and conservation of western Atlantic coral reefs.

    Science.gov (United States)

    Kuffner, Ilsa B; Toth, Lauren T

    2016-08-01

    in conserving Atlantic reefs and the services they provide. © 2016 The Authors. Conservation Biology published by Wiley Periodicals, Inc., on behalf of Society for Conservation Biology.

  5. On the relationship between Atlantic Niño variability and ocean dynamics

    Science.gov (United States)

    Dippe, Tina; Greatbatch, Richard J.; Ding, Hui

    2017-10-01

    The Atlantic Niño is the dominant mode of interannual sea surface temperature (SST) variability in the eastern equatorial Atlantic. Current coupled global climate models struggle to reproduce its variability. This is thought to be partly related to an equatorial SST bias that inhibits summer cold tongue growth. Here, we address the question whether the equatorial SST bias affects the ability of a coupled global climate model to produce realistic dynamical SST variability. We assess this by decomposing SST variability into dynamical and stochastic components. To compare our model results with observations, we employ empirical linear models of dynamical SST that, based on the Bjerknes feedback, use the two predictors sea surface height and zonal surface wind. We find that observed dynamical SST variance shows a pronounced seasonal cycle. It peaks during the active phase of the Atlantic Niño and is then roughly 4-7 times larger than stochastic SST variance. This indicates that the Atlantic Niño is a dynamical phenomenon that is related to the Bjerknes feedback. In the coupled model, the SST bias suppresses the summer peak in dynamical SST variance. Bias reduction, however, improves the representation of the seasonal cold tongue and enhances dynamical SST variability by supplying a background state that allows key feedbacks of the tropical ocean-atmosphere system to operate in the model. Due to the small zonal extent of the equatorial Atlantic, the observed Bjerknes feedback acts quasi-instantaneously during the dynamically active periods of boreal summer and early boreal winter. Then, all elements of the observed Bjerknes feedback operate simultaneously. The model cannot reproduce this, although it hints at a better performance when using bias reduction.

  6. Daily rhythmicity of clock gene transcripts in atlantic cod fast skeletal muscle.

    Science.gov (United States)

    Lazado, Carlo C; Kumaratunga, Hiruni P S; Nagasawa, Kazue; Babiak, Igor; Giannetto, Alessia; Fernandes, Jorge M O

    2014-01-01

    The classical notion of a centralized clock that governs circadian rhythmicity has been challenged with the discovery of peripheral oscillators that enable organisms to cope with daily changes in their environment. The present study aimed to identify the molecular clock components in Atlantic cod (Gadus morhua) and to investigate their daily gene expression in fast skeletal muscle. Atlantic cod clock genes were closely related to their orthologs in teleosts and tetrapods. Synteny was conserved to varying degrees in the majority of the 18 clock genes examined. In particular, aryl hydrocarbon receptor nuclear translocator-like 2 (arntl2), RAR-related orphan receptor A (rora) and timeless (tim) displayed high degrees of conservation. Expression profiling during the early ontogenesis revealed that some transcripts were maternally transferred, namely arntl2, cryptochrome 1b and 2 (cry1b and cry2), and period 2a and 2b (per2a and per2b). Most clock genes were ubiquitously expressed in various tissues, suggesting the possible existence of multiple peripheral clock systems in Atlantic cod. In particular, they were all detected in fast skeletal muscle, with the exception of neuronal PAS (Per-Arnt-Single-minded) domain-containing protein (npas1) and rora. Rhythmicity analysis revealed 8 clock genes with daily rhythmic expression, namely arntl2, circadian locomotor output cycles kaput (clock), npas2, cry2, cry3 per2a, nuclear receptor subfamily 1, group D, member 1 (nr1d1), and nr1d2a. Transcript levels of the myogenic genes myogenic factor 5 (myf5) and muscleblind-like 1 (mbnl1) strongly correlated with clock gene expression. This is the first study to unravel the molecular components of peripheral clocks in Atlantic cod. Taken together, our data suggest that the putative clock system in fast skeletal muscle of Atlantic cod has regulatory implications on muscle physiology, particularly in the expression of genes related to myogenesis.

  7. Daily rhythmicity of clock gene transcripts in atlantic cod fast skeletal muscle.

    Directory of Open Access Journals (Sweden)

    Carlo C Lazado

    Full Text Available The classical notion of a centralized clock that governs circadian rhythmicity has been challenged with the discovery of peripheral oscillators that enable organisms to cope with daily changes in their environment. The present study aimed to identify the molecular clock components in Atlantic cod (Gadus morhua and to investigate their daily gene expression in fast skeletal muscle. Atlantic cod clock genes were closely related to their orthologs in teleosts and tetrapods. Synteny was conserved to varying degrees in the majority of the 18 clock genes examined. In particular, aryl hydrocarbon receptor nuclear translocator-like 2 (arntl2, RAR-related orphan receptor A (rora and timeless (tim displayed high degrees of conservation. Expression profiling during the early ontogenesis revealed that some transcripts were maternally transferred, namely arntl2, cryptochrome 1b and 2 (cry1b and cry2, and period 2a and 2b (per2a and per2b. Most clock genes were ubiquitously expressed in various tissues, suggesting the possible existence of multiple peripheral clock systems in Atlantic cod. In particular, they were all detected in fast skeletal muscle, with the exception of neuronal PAS (Per-Arnt-Single-minded domain-containing protein (npas1 and rora. Rhythmicity analysis revealed 8 clock genes with daily rhythmic expression, namely arntl2, circadian locomotor output cycles kaput (clock, npas2, cry2, cry3 per2a, nuclear receptor subfamily 1, group D, member 1 (nr1d1, and nr1d2a. Transcript levels of the myogenic genes myogenic factor 5 (myf5 and muscleblind-like 1 (mbnl1 strongly correlated with clock gene expression. This is the first study to unravel the molecular components of peripheral clocks in Atlantic cod. Taken together, our data suggest that the putative clock system in fast skeletal muscle of Atlantic cod has regulatory implications on muscle physiology, particularly in the expression of genes related to myogenesis.

  8. The Periodic Table CD.

    Science.gov (United States)

    Banks, Alton J.; Holmes, Jon L.

    1995-01-01

    Describes the characteristics of the digitized version of The Periodic Table Videodisc. Provides details about the organization of information and access to the data via Macintosh and Windows computers. (DDR)

  9. Setting the Periodic Table.

    Science.gov (United States)

    Saturnelli, Annette

    1985-01-01

    Examines problems resulting from different forms of the periodic table, indicating that New York State schools use a form reflecting the International Union of Pure and Applied Chemistry's 1984 recommendations. Other formats used and reasons for standardization are discussed. (DH)

  10. Mitochondrial DNA and Y-chromosome structure at the Mediterranean and Atlantic façades of the Iberian Peninsula.

    Science.gov (United States)

    Santos, Cristina; Fregel, Rosa; Cabrera, Vicente M; Alvarez, Luis; Larruga, Jose M; Ramos, Amanda; López, Miguel A; Pilar Aluja, María; González, Ana M

    2014-01-01

    The aim of this study is to analyze mitochondrial DNA and Y-chromosome lineages in a range of Atlantic and Mediterranean populations of the Iberian Peninsula in search of genetic differences between both façades and to uncover the most probable geographic origin and coalescence ages of lineages. The control region of mitochondrial DNA and haplogroup diagnostic positions were analyzed in 575 subjects and Y-chromosome markers were typed in 260 unrelated males. Moreover, previously published data were compiled and used in the analyses. The level of genetic structure deduced from uniparental markers for the Iberian Peninsula was weak, with stronger Atlantic versus Mediterranean than North to South differentiation and larger diversities in the South. In general, mitochondrial DNA haplogroups had mainly Paleolithic and Mesolithic coalescences in Europe, although some of them, ruling out drift effects, seem to have younger implantation in Central Europe and the Atlantic areas than in the Mediterranean (I, J, J2a, T1, and W) while others as N1 and X could have reached the Iberian Peninsula at the Neolithic transition. On the other hand, younger coalescence ages are being proposed for the arriving or spread of the bulk of Y-chromosome lineages in Europe. The major haplotypic affinities found for all the Iberian Peninsula regions were always with North Africa and the Atlantic Islands. These results draw an Atlantic network that clearly resembles those of the Megalithic Copper and Bronze cultures at this part of Europe. Copyright © 2013 Wiley Periodicals, Inc.

  11. Mammal occurrence and roadkill in two adjacent ecoregions (Atlantic Forest and Cerrado in south-western Brazil

    Directory of Open Access Journals (Sweden)

    Nilton C. Cáceres

    2010-10-01

    Full Text Available This paper examines the frequencies of mammal roadkill in two adjacent biogeographic ecoregions (Atlantic Forest and Cerrado of Brazil. Mammals were recorded during a seven-year period and over 3,900 km of roads, in order to obtain data for frequencies of species in habitats (sites and frequencies of species killed by cars on roads. Sites (n = 80 within ecoregions (Cerrado, n = 57; Atlantic Forest, n = 23 were searched for records of mammals. Species surveyed in the entire region totaled 33, belonging to nine orders and 16 families. In the Cerrado, 31 species were recorded in habitats; of these, 25 were found dead on roads. In the Atlantic Forest ecoregions, however, we found 21 species in habitats, 16 of which were also found dead on roads. There was no overall significant difference between ecoregions for frequencies of occurrence in habitats or for roadkills, but there were differences between individual species. Hence, anteaters were mostly recorded in the Cerrado ecoregion, whereas caviomorph rodents tended to be more frequent in the Atlantic Forest ecoregion (seen mainly by roadkills. The greater number of species (overall and threatened and the greater abundance of species records in the Cerrado suggest that this ecoregion has a greater biodiversity and is better conserved than the Atlantic Forest ecoregion, in the state of Mato Grosso do Sul, south-western Brazil.

  12. Effect of rabdosia rubescens combined with new assistant chemotherapy on serum CA199, CEA, CA15-3 and T lymphocyte subsets in patients with breast cancer

    Directory of Open Access Journals (Sweden)

    Lei Xi

    2018-07-01

    Full Text Available Objective: To study the effects of Rabdosia rubescens combined with neoadjuvant chemotherapy on serum CA199, CEA, CA15-3 levels and T lymphocyte subsets in patients with breast cancer. Methods: A total of 70 patients with breast cancer in our hospital were enrolled as the subjects of this study. The subjects were divided into control group (n=35 and treatment group (n=35 randomly. Patients in the control group were treated with new assistant chemotherapy, while those who were in the treatment group were treated with rabdosia rubescens combined with new assistant chemotherapy. The two groups of patients were treated for 3 periods. The serum CA199, CEA, CA15-3 levels and peripheral blood CD4+, CD8+, CD4+/CD8+ cells of the two groups before and after treatment were compared. Results: There were no significantly differences among the serum CA199, CEA, CA15-3 levels and peripheral blood CD4+, CD8+, CD4+/CD8+ cells of the two groups before treatment. The serum CA199, CEA and CA15-3 levels of the two groups after treatment were significantly lower than those before treatment, besides, the serum CA199, CEA and CA15-3 levels of the treatment group were significantly lower than those of the control group. The peripheral blood CD4+, CD4+/ CD8+ cells of the control group after treatment were significantly lower than before treatment, and the peripheral blood CD4+, CD4+/CD8+ cells of the treatment group after treatment were significantly higher than those of the control group. Conclusion: Rabdosia rubescens combined with new assistant chemotherapycan can significantly reduce the serum CA199, CEA and CA15-3 levels, and improve peripheral blood CD4+, CD8+, CD4+/CD8+ levels of patients with breast cancer. It is worthy of clinical application.

  13. Continuously Tunable Ca2+ Regulation of RNA-Edited CaV1.3 Channels

    Directory of Open Access Journals (Sweden)

    Hojjat Bazzazi

    2013-10-01

    Full Text Available CaV1.3 ion channels are dominant Ca2+ portals into pacemaking neurons, residing at the epicenter of brain rhythmicity and neurodegeneration. Negative Ca2+ feedback regulation of CaV1.3 channels (CDI is therefore critical for Ca2+ homeostasis. Intriguingly, nearly half the CaV1.3 transcripts in the brain are RNA edited to reduce CDI and influence oscillatory activity. It is then mechanistically remarkable that this editing occurs precisely within an IQ domain, whose interaction with Ca2+-bound calmodulin (Ca2+/CaM is believed to induce CDI. Here, we sought the mechanism underlying the altered CDI of edited channels. Unexpectedly, editing failed to attenuate Ca2+/CaM binding. Instead, editing weakened the prebinding of Ca2+-free CaM (apoCaM to channels, which proves essential for CDI. Thus, editing might render CDI continuously tunable by fluctuations in ambient CaM, a prominent effect we substantiate in substantia nigral neurons. This adjustability of Ca2+ regulation by CaM now looms as a key element of CNS Ca2+ homeostasis.

  14. Reflection of equatorial Kelvin waves at eastern ocean boundaries Part II: Pacific and Atlantic Oceans

    Directory of Open Access Journals (Sweden)

    J. Soares

    1999-06-01

    Full Text Available The effect of viscosity, non linearities, incident wave period and realistic eastern coastline geometry on energy fluxes are investigated using a shallow water model with a spatial resolution of 1/4 degree in both meridional and zonal directions. Equatorial and mid-latitude responses are considered. It is found that (1 the influence of the coastline geometry and the incident wave period is more important for the westward energy flux than for the poleward flux, and (2 the effect of the inclination of the eastern ocean boundary on the poleward energy flux, for the Pacific and Atlantic Oceans, decline as the period of the incident wave increases. Furthermore, the model simulations suggest that the poleward energy fluxes from meridional boundaries give plausible results for motions of seasonal and annual periods. For comparatively shorter periods, a realistic coastline geometry has to be included for more accurate results. It is recommended that any numerical model involving the reflection of baroclinic Rossby waves (of intraseasonal, seasonal or annual periods on the eastern Pacific or Atlantic Oceans, should consider the effect of the coastline geometry in order to improve the accuracy of the results.Key words. Oceanography: general (climate and interannual variability; equatorial oceanography. Oceanography: physical (eastern boundary currents.

  15. Identifying Important Atlantic Areas for the conservation of Balearic shearwaters: Spatial overlap with conservation areas

    Science.gov (United States)

    Pérez-Roda, Amparo; Delord, Karine; Boué, Amélie; Arcos, José Manuel; García, David; Micol, Thierry; Weimerskirch, Henri; Pinaud, David; Louzao, Maite

    2017-07-01

    Marine protected areas (MPAs) are considered one of the main tools in both fisheries and conservation management to protect threatened species and their habitats around the globe. However, MPAs are underrepresented in marine environments compared to terrestrial environments. Within this context, we studied the Atlantic non-breeding distribution of the southern population of Balearic shearwaters (Puffinus mauretanicus) breeding in Eivissa during the 2011-2012 period based on global location sensing (GLS) devices. Our objectives were (1) to identify overall Important Atlantic Areas (IAAs) from a southern population, (2) to describe spatio-temporal patterns of oceanographic habitat use, and (3) to assess whether existing conservation areas (Natura 2000 sites and marine Important Bird Areas (IBAs)) cover the main IAAs of Balearic shearwaters. Our results highlighted that the Atlantic staging (from June to October in 2011) dynamic of the southern population was driven by individual segregation at both spatial and temporal scales. Individuals ranged in the North-East Atlantic over four main IAAs (Bay of Biscay: BoB, Western Iberian shelf: WIS, Gulf of Cadiz: GoC, West of Morocco: WoM). While most individuals spent more time on the WIS or in the GoC, a small number of birds visited IAAs at the extremes of their Atlantic distribution range (i.e., BoB and WoM). The chronology of the arrivals to the IAAs showed a latitudinal gradient with northern areas reached earlier during the Atlantic staging. The IAAs coincided with the most productive areas (higher chlorophyll a values) in the NE Atlantic between July and October. The spatial overlap between IAAs and conservation areas was higher for Natura 2000 sites than marine IBAs (areas with and without legal protection, respectively). Concerning the use of these areas, a slightly higher proportion of estimated positions fell within marine IBAs compared to designated Natura 2000 sites, with Spanish and Portuguese conservation

  16. Arctic climatechange and its impacts on the ecology of the North Atlantic.

    Science.gov (United States)

    Greene, Charles H; Pershing, Andrew J; Cronin, Thomas M; Ceci, Nicole

    2008-11-01

    Arctic climate change from the Paleocene epoch to the present is reconstructed with the objective of assessing its recent and future impacts on the ecology of the North Atlantic. A recurring theme in Earth's paleoclimate record is the importance of the Arctic atmosphere, ocean, and cryosphere in regulating global climate on a variety of spatial and temporal scales. A second recurring theme in this record is the importance of freshwater export from the Arctic in regulating global- to basin-scale ocean circulation patterns and climate. Since the 1970s, historically unprecedented changes have been observed in the Arctic as climate warming has increased precipitation, river discharge, and glacial as well as sea-ice melting. In addition, modal shifts in the atmosphere have altered Arctic Ocean circulation patterns and the export of freshwater into the North Atlantic. The combination of these processes has resulted in variable patterns of freshwater export from the Arctic Ocean and the emergence of salinity anomalies that have periodically freshened waters in the North Atlantic. Since the early 1990s, changes in Arctic Ocean circulation patterns and freshwater export have been associated with two types of ecological responses in the North Atlantic. The first of these responses has been an ongoing series of biogeographic range expansions by boreal plankton, including renewal of the trans-Arctic exchanges of Pacific species with the Atlantic. The second response was a dramatic regime shift in the shelf ecosystems of the Northwest Atlantic that occurred during the early 1990s. This regime shift resulted from freshening and stratification of the shelf waters, which in turn could be linked to changes in the abundances and seasonal cycles of phytoplankton, zooplankton, and higher trophic-level consumer populations. It is predicted that the recently observed ecological responses to Arctic climate change in the North Atlantic will continue into the near future if current trends

  17. Mechanisms of meridional transport processes in the tropical Atlantic; Mechanismen meridionaler Transportprozesse im tropischen Atlantik

    Energy Technology Data Exchange (ETDEWEB)

    Kroeger, J.

    2001-07-01

    Meridional transport processes of water masses and tracers in the subtropical and tropical Atlantic are investigated using a regional eddy resolving model of the wind driven and thermohaline circulation. Analytical emphasis is on float simulations in the model which, complementary to Eulerian means, represent the Lagrangian view and give further insight into the spreading and pathways of characteristic water masses in this area. In the tropics and subtropics shallow 3-dimensional circulation cells are superimposed on the northward warm water transfer within the deep reaching thermohaline overturning cell (MOC) as part of the global ''Conveyor Belt''. Under present-day climate conditions the model shows that the equatorial thermocline is exclusively ventilated by subsurface flow within the tropical-subtropical cell (STC) of the South Atlantic. Only with a prescribed ''Conveyor-off''-Mode the STC of the North Atlantic contributes to this ventilation process with equal amounts. Throughout the year the interhemispheric transport of surface and central water masses of South Atlantic origin into the Caribbean Sea is dominated by zonal detours to the east as a consequence of the interplay of several retroflection events occuring in the North Atlantic. The eulerian mean flow field in the deep layer postulates the interhemispheric mass transport into the South Atlantic to be confined entirely to the western boundary, whereas Lagrangian means indicate intermittent eastward excursions along the equator, related to seasonally alternating zonal currents due to long Rossby waves. It was suggested that the observed characteristic eastward maximum of tracer concentrations along the equator is a consequence of rectifying effects of single or interacting equatorial waves. The model does not validate this hypothesis. The response to transport anomalies of subpolar origin and long periodicity is subject to different time-scales in both

  18. Summer weather characteristics and periodicity observed over the period 1888-2013 in the region of Belgrade, Serbia

    Science.gov (United States)

    Vujović, Dragana; Todorović, Nedeljko; Paskota, Mira

    2017-02-01

    With the goal of finding summer climate patterns in the region of Belgrade (Serbia) over the period 1888-2013, different techniques of multivariate statistical analysis were used in order to analyze the simultaneous changes of a number of climatologic parameters. An increasing trend of the mean daily minimum temperature was detected. In the recent decades (1960-2013), this increase was much more pronounced. The number of days with the daily minimum temperature greater or equal to 20 °C also increased significantly. Precipitation had no statistically significant trend. Spectral analysis showed a repetitive nature of the climatologic parameters which had periods that roughly can be classified into three groups, with the durations of the following: (1) 6 to 7 years, (2) 10 to 18 years, and (3) 21, 31, and 41 years. The temperature variables mainly had one period of repetitiveness of 5 to 7 years. Among other variables, the correlations of regional fluctuations of the temperature and precipitation and atmospheric circulation indices were analyzed. The North Atlantic oscillation index had the same periodicity as that of the precipitation, and it was not correlated to the temperature variables. Atlantic multidecadal oscillation index correlated well to the summer mean daily minimum and summer mean temperatures. The underlying structure of the data was analyzed by principal component analysis, which detected the following four easily interpreted dimensions: More sunshine-Higher temperature, Precipitation, Extreme heats, and Changeable summer.

  19. Menstrual cycle variability of CA 72-4 in healthy women.

    Science.gov (United States)

    Yarcı Gursoy, Aslı; Kiseli, Mine; Ozdemir, Sedat; Şeker, Rabia; Caglar, Gamze Sinem

    2015-01-01

    CA 72-4 is not approved as a tumor marker but has been used as an adjunct marker in gynecological practice. The study aims to evaluate the menstrual cycle variability of CA 72-4 in a population of healthy women. Forty apparently healthy regularly menstruating subjects were included in the cross-sectional study designed in the University Obstetrics and Gynecology outpatient clinic. Venous blood samples from each participant were collected twice: first at the follicular phase (2nd-5th days of the menstrual cycle) for FSH, estradiol, CA 125, CA 72-4 and the other at the luteal phase (21st-24th days of the menstrual cycle) for progesterone, CA 125 and CA 72-4 levels. CA 72-4 values were similar in follicular and luteal phase of the menstrual cycle in apparently healthy regularly menstruating subjects (1.15U/mL (0.2-5.4) vs 1.15 U/mL (0.56-6.3); p=0.326 respectively). Ovulatory or smoking status did not have an effect on CA 72-4 values (p>0.05). This first clinical study about the menstrual cycle variability of CA 72-4 revealed that the menstrual cycle does not have a significant impact on CA 72-4 values and that it can be measured at any time during the menstrual period. Copyright © 2014 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

  20. Periodicity in magmatic systems

    Science.gov (United States)

    Caricchi, Luca

    2016-04-01

    Magmatic systems show periodicity in productivity, magma chemistry and dynamics of volcanic eruptions. The timescales over which such parameters change are highly variable and ranges between several tens of millions of years down to few hundredths of thousands years. While magmatic activity appears modulated at various frequencies, the lifetime of single volcanic systems, the duration of emplacement of single plutons, or the timespan over which a given volcanic region is active, appear to last for distinct but characteristic periods of time. Hundredths of thousands of years is a typical number for the range of zircon crystallisation ages in the products of large eruptions or for the lifetime of single plutons, while activity in volcanic regions or the duration of emplacement of crustal batholiths appears to last up to about 10 Ma. Several mechanisms such as variable magma productivity in the mantle, delamination, thermal and mechanical maturation of the crust have been proposed to modulate magmatic activity. All these processes indeed contribute to modulate the periodicity of magmatic activity, but because certain timescales are recurrent, some fundamental processes must play a fundamental role in regulating the "tempo" of magmatism. Are transitions of behaviour finally the product of major changes in mantle dynamics or is the crust the plays the pivotal role in modulating periodic variations observed in magmatic systems? In this contribution I will provide an overview of existing data on periodicity of magmatic systems and use thermal modelling to show that periodic variations of magma chemistry and the physical properties of magmas are an inexorable consequence of the evolution of the thermal budget of magmatic systems. I hope to trigger discussion and collaborations between experts of geodynamics and magmatism to establish relationships between periodicity, mantle and crustal processes.

  1. Changes in CaCO3 Burial Trump the Biological Pump

    Science.gov (United States)

    Toggweiler, J.; Dunne, J. P.

    2008-12-01

    hot spots can also move from place to place in response to changes in circulation. The main hot spots today are the eastern Atlantic and southern Indian; the main hot spot during the last glacial was the equatorial Pacific. Renewed deep-water formation in the Atlantic at the end of the last ice age shifted the locus of CaCO3 burial back to the Atlantic and southern Indian and led to a huge drawdown in global alkalinity, which is ongoing today and accounts for most of the deglacial rise in atmospheric CO2.

  2. Tracking the Atlantic Multidecadal Oscillation through the last 8,000 years

    DEFF Research Database (Denmark)

    Knudsen, Mads Faurschou; Seidenkrantz, Marit-Solveig; Jacobsen, B. H.

    2011-01-01

    of the AMO is uncertain, and it remains unknown whether it represents a persistent periodic driver in the climate system, or merely a transient feature. Here, we show that distinct, ~55- to 70-year oscillations characterized the North Atlantic ocean-atmosphere variability over the past 8,000 years. We test...... and reject the hypothesis that this climate oscillation was directly forced by periodic changes in solar activity. We therefore conjecture that a quasi-persistent ~55- to 70-year AMO, linked to internal ocean-atmosphere variability, existed during large parts of the Holocene. Our analyses further suggest...

  3. Reduced Anxiety in Forensic Inpatients after a Long-Term Intervention with Atlantic Salmon

    Science.gov (United States)

    Hansen, Anita L.; Olson, Gina; Dahl, Lisbeth; Thornton, David; Grung, Bjørn; Graff, Ingvild E.; Frøyland, Livar; Thayer, Julian F.

    2014-01-01

    The aim of the present study was to investigate the effects of Atlantic salmon consumption on underlying biological mechanisms associated with anxiety such as heart rate variability (HRV) and heart rate (HR) as well as a measure of self-reported anxiety. Moreover, these biological and self-reported outcome measures were investigated in relation to specific nutrients; vitamin D status, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Ninety-five male forensic inpatients were randomly assigned into a Fish (Atlantic salmon three times per week from September to February) or a Control group (alternative meal, e.g., chicken, pork, or beef three times per week during the same period). HRV measured as the root mean square of successive differences (rMSSD), HR, state- and trait-anxiety (STAI), were assessed before (pre-test) and at the end of the 23 weeks dietary intervention period (post-test). The Fish group showed significant improvements in both rMSSD and HR. The Fish group also showed significant decreases in state-anxiety. Finally, there was a positive relationship between rMSSD and vitamin D status. The findings suggest that Atlantic salmon consumption may have an impact on mental health related variables such as underlying mechanisms playing a key role in emotion-regulation and state-anxiety. PMID:25431880

  4. Estimating sea-level allowances for Atlantic Canada under conditions of uncertain sea-level rise

    Directory of Open Access Journals (Sweden)

    B. Greenan

    2015-03-01

    Full Text Available This paper documents the methodology of computing sea-level rise allowances for Atlantic Canada in the 21st century under conditions of uncertain sea-level rise. The sea-level rise allowances are defined as the amount by which an asset needs to be raised in order to maintain the same likelihood of future flooding events as that site has experienced in the recent past. The allowances are determined by combination of the statistics of present tides and storm surges (storm tides and the regional projections of sea-level rise and associated uncertainty. Tide-gauge data for nine sites from the Canadian Atlantic coast are used to derive the scale parameters of present sea-level extremes using the Gumbel distribution function. The allowances in the 21st century, with respect to the year 1990, were computed for the Intergovernmental Panel on Climate Change (IPCC A1FI emission scenario. For Atlantic Canada, the allowances are regionally variable and, for the period 1990–2050, range between –13 and 38 cm while, for the period 1990–2100, they range between 7 and 108 cm. The negative allowances in the northern Gulf of St. Lawrence region are caused by land uplift due to glacial isostatic adjustment (GIA.

  5. Tracking the Atlantic Multidecadal Oscillation through the last 8,000 years.

    Science.gov (United States)

    Knudsen, Mads Faurschou; Seidenkrantz, Marit-Solveig; Jacobsen, Bo Holm; Kuijpers, Antoon

    2011-02-01

    Understanding the internal ocean variability and its influence on climate is imperative for society. A key aspect concerns the enigmatic Atlantic Multidecadal Oscillation (AMO), a feature defined by a 60- to 90-year variability in North Atlantic sea-surface temperatures. The nature and origin of the AMO is uncertain, and it remains unknown whether it represents a persistent periodic driver in the climate system, or merely a transient feature. Here, we show that distinct, ∼55- to 70-year oscillations characterized the North Atlantic ocean-atmosphere variability over the past 8,000 years. We test and reject the hypothesis that this climate oscillation was directly forced by periodic changes in solar activity. We therefore conjecture that a quasi-persistent ∼55- to 70-year AMO, linked to internal ocean-atmosphere variability, existed during large parts of the Holocene. Our analyses further suggest that the coupling from the AMO to regional climate conditions was modulated by orbitally induced shifts in large-scale ocean-atmosphere circulation.

  6. Climatic bisection of the last interglacial warm period in the Polar North Atlantic

    Science.gov (United States)

    Bauch, Henning A.; Kandiano, Evguenia S.; Helmke, Jan; Andersen, Nils; Rosell-Mele, Antoni; Erlenkeuser, Helmut

    2011-07-01

    New multiproxy marine data of the Eemian interglacial (MIS5e) from the Norwegian Sea manifest a cold event with near-glacial surface ocean summer temperatures (3-4 °C). This mid-Eemian cooling divided the otherwise relatively warm interglacial climate and was associated with widespread expansions of winter sea-ice and polar water masses due to changes in atmospheric circulation and ocean stability. While the data also verify a late rather than early last interglacial warm peak, which is in general disharmony with northern hemisphere insolation maximum and the regional climatic progression of the early Holocene, the cold event itself was likely instrumental for delaying the last interglacial climate development in the Polar North when compared with regions farther south. Such a 'climatic decoupling' of the Polar region may bear profound implications for the employment of Eemian conditions to help evaluate the present and future state of the Arctic cryosphere during a warming interglacial.

  7. Do the recent severe droughts in the Amazonia have the same period of length?

    CERN Document Server

    Zou, Yong; Sampaio, Gilvan; Mário, Antônio; Kurths, Jürgen

    2015-01-01

    We propose a new measure based on drought period length to assess the temporal difference between the recent two severe droughts of 2005 and 2010 in the Amazonia. The sensitivity of the measure is demonstrated by disclosing the distinct spatial responding mechanisms of the Northeastern and Southwestern Amazon (NA, SA) to the surrounding sea surface temperature (SST) variabilities. The Pacific and Atlantic oceans have different roles on the precipitation patterns in Amazonia. More specifically, the very dry periods in the NA are influenced by El Ni\\~no events, while the very dry periods in the SA are affected by the anomalously warming of the SST in the North Atlantic. We show convincingly that the drought 2005 hit SA, which is caused by the North Atlantic only. There are two phases in the drought 2010: (i) it was started in the NA in August 2009 affected by the El Ni\\~no event, and (ii) later shifted the center of action to SA resulted from anomalously high SST in North Atlantic, which further intensifies the...

  8. Influence of environmental changes in the north-western Atlantic Ocean on a parasite, Echinorhynchus gadi (Acanthocephala) of Atlantic cod ( Gadus morhua) occurring off coastal Labrador, Canada.

    Science.gov (United States)

    Khan, R A

    2008-09-01

    A study was conducted to determine the influence of environmental change on an endoparasite, Echinorhynchus gadi (Acanthocephala) of Atlantic cod (Gadus morhua) over a 30-year period off the coast of Labrador in the north-western Atlantic, North Atlantic Fisheries Organization subareas 2J-3K. Cod, once an abundant fish species that had been commercially exploited for many decades, declined precipitously during the mid-1980s onwards. This decline was attributed to climatic changes that affected the entire food chain from zooplankton to fish, sea birds and marine mammals. A monitoring programme was introduced, sampling cod by otter trawling using research vessels. The fish, after capture, were frozen at - 20 degrees C, subsequently thawed and the digestive tract removed and examined for the parasite in 2006. Data from samples taken in 1976, 1980-81, 1986, 1990, 2000 and 2003 were compared statistically with those collected in 2006. The results indicate a decline in the prevalence and mean abundance of E. gadi in 1986 with a minimum in 2000 but increasing gradually in 2003 and 2006. These changes were coincident initially with a decline of oceanic temperature and the entire food web, including capelin (Mallotus villosus), a preferred prey of cod and primary source of E. gadi. The increase in prevalence and mean abundance of the parasite in 2006 were associated with an increase of oceanic temperature and the return of small schools of capelin to offshore areas. Cod older than 4 years harboured a greater abundance of E. gadi than younger fish, while no difference was observed between the sexes. The results suggest that the abundance of E. gadi can be useful as a bioindicator of environmental changes in the north-western Atlantic.

  9. Imaging Ca2+ with a Fluorescent Rhodol.

    Science.gov (United States)

    Contractor, Alisha A; Miller, Evan W

    2018-01-16

    Ca2+ mediates a host of biochemical and biophysical signaling processes in cells. The development of synthetic, Ca2+-sensitive fluorophores has played an instrumental role in our understanding of the temporal and spatial dynamics of Ca2+. Coupling Ca2+-selective ligands to fluorescent reporters has provided a wealth of excellent indicators that span the visible excitation and emission spectrum and possess Ca2+ affinities suited to a variety of cellular contexts. One underdeveloped area is the use of hybrid rhodamine/fluorescein fluorophores, or rhodols, in the context of Ca2+ sensing. Rhodols are bright and photostable and have good two-photon absorption cross sections (σTPA), making them excellent candidates for incorporation into Ca2+-sensing scaffolds. Here, we present the design, synthesis, and application of rhodol Ca2+ sensor 1 (RCS-1), a chlorinated pyrrolidine-based rhodol. RCS-1 possesses a Ca2+ binding constant of 240 nM and a 10-fold turn response to Ca2+. RCS-1 effectively absorbs infrared light and has a σTPA of 76 GM at 840 nm, 3-fold greater than that of its fluorescein-based counterpart. The acetoxy-methyl ester of RCS-1 stains the cytosol of live cells, enabling observation of Ca2+ fluctuations and cultured neurons using both one- and two-photon illumination. Together, these results demonstrate the utility of rhodol-based scaffolds for Ca2+ sensing using two-photon illumination in neurons.

  10. Ca2+ Dependence of Synaptic Vesicle Endocytosis.

    Science.gov (United States)

    Leitz, Jeremy; Kavalali, Ege T

    2016-10-01

    Ca(2+)-dependent synaptic vesicle recycling is essential for structural homeostasis of synapses and maintenance of neurotransmission. Although, the executive role of intrasynaptic Ca(2+) transients in synaptic vesicle exocytosis is well established, identifying the exact role of Ca(2+) in endocytosis has been difficult. In some studies, Ca(2+) has been suggested as an essential trigger required to initiate synaptic vesicle retrieval, whereas others manipulating synaptic Ca(2+) concentrations reported a modulatory role for Ca(2+) leading to inhibition or acceleration of endocytosis. Molecular studies of synaptic vesicle endocytosis, on the other hand, have consistently focused on the roles of Ca(2+)-calmodulin dependent phosphatase calcineurin and synaptic vesicle protein synaptotagmin as potential Ca(2+) sensors for endocytosis. Most studies probing the role of Ca(2+) in endocytosis have relied on measurements of synaptic vesicle retrieval after strong stimulation. Strong stimulation paradigms elicit fusion and retrieval of multiple synaptic vesicles and therefore can be affected by several factors besides the kinetics and duration of Ca(2+) signals that include the number of exocytosed vesicles and accumulation of released neurotransmitters thus altering fusion and retrieval processes indirectly via retrograde signaling. Studies monitoring single synaptic vesicle endocytosis may help resolve this conundrum as in these settings the impact of Ca(2+) on synaptic fusion probability can be uncoupled from its putative role on synaptic vesicle retrieval. Future experiments using these single vesicle approaches will help dissect the specific role(s) of Ca(2+) and its sensors in synaptic vesicle endocytosis. © The Author(s) 2015.

  11. Isopycnal diffusivity in the tropical North Atlantic oxygen minimum zone

    Science.gov (United States)

    Köllner, Manuela; Visbeck, Martin; Tanhua, Toste; Fischer, Tim

    2017-04-01

    Isopycnal diffusivity plays an important role in the ventilation of the Eastern Tropical North Atlantic (ETNA) Oxygen Minimum Zone (OMZ). Lateral tracer transport is described by isopycnal diffusivity and mean advection of the tracer (e.g. oxygen), together they account for up to 70% of the oxygen supply for the OMZ. One of the big challenges is to separate diffusivity from advection. Isopycnal diffusivity was estimated to be Ky=(500 ± 200) m2 s-1 and Kx=(1200 ± 600) m2 s-1 by Banyte et. al (2013) from a Tracer Release Experiment (TRE). Hahn et al. (2014) estimated a meridional eddy diffusivity of 1350 m2 s-1 at 100 m depth decaying to less than 300 m2 s-1 below 800 m depth from repeated ship sections of CTD and ADCP data in addition with hydrographic mooring data. Uncertainties of the estimated diffusivities were still large, thus the Oxygen Supply Tracer Release Experiment (OSTRE) was set up to estimate isopycnal diffusivity in the OMZ using a newly developed sampling strategy of a control volume. The tracer was released in 2012 in the core of the OMZ at approximately 410 m depth and mapped after 6, 15 and 29 months in a regular grid. In addition to the calculation of tracer column integrals from vertical tracer profiles a new sampling method was invented and tested during two of the mapping cruises. The mean eddy diffusivity during OSTRE was found to be about (300 ± 130) m2 s-1. Additionally, the tracer has been advected further to the east and west by zonal jets. We compare different analysis methods to estimate isopycnal diffusivity from tracer spreading and show the advantage of the control volume surveys and control box approach. From the control box approach we are estimating the strength of the zonal jets within the OMZ core integrated over the TRE time period. References: Banyte, D., Visbeck, M., Tanhua, T., Fischer, T., Krahmann, G.,Karstensen, J., 2013. Lateral Diffusivity from Tracer Release Experiments in the Tropical North Atlantic Thermocline

  12. The South Atlantic Coupled Variability and the South Atlantic Convergence Zone

    Science.gov (United States)

    Bombardi, Rodrigo Jose

    The dominant mode of coupled variability over the South Atlantic Ocean is known as "South Atlantic Dipole" (SAD) and is characterized by a dipole in sea surface temperature (SST) anomalies with centers over the tropical and the extratropical South Atlantic. Previous studies have shown that variations in SST related to SAD modulate large-scale patterns of precipitation over the Atlantic Ocean. Here we show that variations in the South Atlantic SST are associated with changes in daily precipitation over eastern South America. This study is based on observational and regional atmospheric modeling. Rain gauge precipitation, satellite derived sea surface temperature and reanalysis data are used to investigate the variability of the subtropical and tropical South Atlantic and impacts on precipitation. SAD phases are assessed by performing Singular Value Decomposition (SVD) analysis of sea level pressure and SST anomalies. We show that during neutral El Nino-Southern Oscillation (ENSO) events, SAD plays an important role in modulating cyclogenesis and the characteristics of the South Atlantic Convergence Zone (SACZ). Positive SST anomalies over the extratropical South Atlantic (SAD negative phase) are related to increased cyclogenesis near southeast Brazil as well as the migration of extratropical cyclones further north. As a consequence, these systems organize convection and increase precipitation over eastern South America. Numerical experiments forced with prescribed SST anomalies showed that even though the Atlantic SST affects the position of the cyclone associated with the SACZ, the atmospheric response and precipitation patters over land were opposite from the observational results. On the other hand, experiments forced with prescribed anomalous driving fields showed that the atmospheric component of SAD plays a significant role for the right position and intensity of precipitation associated with the SACZ. SAD negative anomalies provide the low-level and upper

  13. Spatiotemporal relationships between earthquakes of the mid-Atlantic Ridge and the Atlantic continental margins

    Science.gov (United States)

    Bolarinwa, Oluwaseyi J.

    The seismicity of the mid Atlantic Ridge (MAR) was compared in space and time with the seismicity along the Atlantic continental margins of Europe, Africa, North America, the Carribean and South America in a bid to appraise the level of influence of the ridge push force at the MAR on the Atlantic coastal seismicity. By analyzing the spatial and temporal patterns of many earthquakes (along with the patterns in their stress directions) in diverse places with similar tectonic settings, it is hoped that patterns that might be found indicate some of the average properties of the forces that are causing the earthquakes. The spatial analysis of the dataset set used shows that areas with higher seismic moment release along the north MAR spatially correlate with areas with relatively lower seismic moment release along the north Atlantic continental margins (ACM) and vice versa. This inverse spatial correlation observed between MAR seismicity and ACM seismicity might be due to the time (likely a long time) it takes stress changes from segments of the MAR currently experiencing high seismic activity to propagate to the associated passive margin areas presently experiencing relatively low seismic activity. Furthermore, the number of Atlantic basin and Atlantic coast earthquakes occurring away from the MAR is observed to be independent of the proximity of earthquake's epicenters from the MAR axis. The effect of local stress as noted by Wysession et al. (1995) might have contributed to the independence of Atlantic basin and Atlantic coast earthquake proximity from the MAR. The Latchman (2011) observation of strong earthquakes on a specific section of the MAR being followed by earthquakes on Trinidad and Tobago was tested on other areas of the MAR and ACM. It was found that that the temporal delay observed by Latchman does not exist for the seismicity along other areas along the MAR and ACM. Within the time window used for this study, it appears that seismicity is occurring

  14. An Inhibitory Effect of Extracellular Ca2+ on Ca2+-Dependent Exocytosis

    Science.gov (United States)

    Wang, Yeshi; Chen, Xiaowei; Sun, Lei; Guo, Ning; Zheng, Hui; Zheng, Lianghong; Ruat, Martial; Han, Weiping; Zhang, Claire Xi; Zhou, Zhuan

    2011-01-01

    Aim Neurotransmitter release is elicited by an elevation of intracellular Ca2+ concentration ([Ca2+]i). The action potential triggers Ca2+ influx through Ca2+ channels which causes local changes of [Ca2+]i for vesicle release. However, any direct role of extracellular Ca2+ (besides Ca2+ influx) on Ca2+-dependent exocytosis remains elusive. Here we set out to investigate this possibility on rat dorsal root ganglion (DRG) neurons and chromaffin cells, widely used models for studying vesicle exocytosis. Results Using photolysis of caged Ca2+ and caffeine-induced release of stored Ca2+, we found that extracellular Ca2+ inhibited exocytosis following moderate [Ca2+]i rises (2–3 µM). The IC50 for extracellular Ca2+ inhibition of exocytosis (ECIE) was 1.38 mM and a physiological reduction (∼30%) of extracellular Ca2+ concentration ([Ca2+]o) significantly increased the evoked exocytosis. At the single vesicle level, quantal size and release frequency were also altered by physiological [Ca2+]o. The calcimimetics Mg2+, Cd2+, G418, and neomycin all inhibited exocytosis. The extracellular Ca2+-sensing receptor (CaSR) was not involved because specific drugs and knockdown of CaSR in DRG neurons did not affect ECIE. Conclusion/Significance As an extension of the classic Ca2+ hypothesis of synaptic release, physiological levels of extracellular Ca2+ play dual roles in evoked exocytosis by providing a source of Ca2+ influx, and by directly regulating quantal size and release probability in neuronal cells. PMID:22028769

  15. Diagenesis of lower Cretaceous pelagic carbonates, North Atlantic: Paleoceanographic signals obscured

    Science.gov (United States)

    Frank, T.D.; Arthur, M.A.; Dean, W.E.

    1999-01-01

    The stable isotope and minor element geochemistry of Neocomian (Lower Cretaceous) pelagic carbonates of the North Atlantic Basin (Deep Sea Drilling Project Sites 105, 367, 387, 391, and 603) was examined to develop a diagenetic model for pelagic limestones. In particular, we hoped to test the fidelity of whole-rock geochemical records as paleoceanographic indicators for pelagic deposits of pre-Aptian age, in which individual microfossils are not available for analysis. Data indicate that in addition to depth of burial, rhythmic variations in primary carbonate content have strongly controlled diagenetic patterns and associated geochemical signatures in these Neocomian sequences. Samples become increasingly depleted in Sr and 18O with increasing CaCO3 content. Within individual sedimentary sections, substantial decreases in Sr/Ca ratios and ??18O values are evident over a range of 4 to 98% CaCO3. However, even over a relatively narrow range of 50 to 98% CaCO3 a 2.5%c variation in ??18O values and a change of a factor of 1.7 in Sr/Ca ratios are observed. Carbon isotope compositions do not vary as extensively with CaCO3 content, but carbonate-rich intervals tend to be relatively depleted in 13C. Petrographic analysis reveals that these geochemical patterns are related to the transfer of CaCO3 from carbonate-poor intervals (calcareous shales and marlstones) to adjacent carbonate-rich intervals (limestones) during burial compaction and pressure solution. This process results in the addition of diagenetic cement to carbonate-rich intervals to produce a bulk composition that is relatively depleted in Sr and 18O and, at the same time, enables the retention of more-or-less primary carbonate that is relatively enriched in Sr and 18O in adjacent carbonate-poor intervals. Thus, although cyclic variations in CaCO3 content are primary in the Neocomian sequences examined, measured variations in Sr/Ca ratios and ??18O values are not and, as such, do not provide reliable proxies for

  16. Response of the North Atlantic subpolar gyre to persistent North Atlantic oscillation like forcing

    Energy Technology Data Exchange (ETDEWEB)

    Lohmann, Katja; Bentsen, Mats [Nansen Environmental and Remote Sensing Center, Bergen (Norway); Bjerknes Center for Climate Research, Bergen (Norway); Drange, Helge [Nansen Environmental and Remote Sensing Center, Bergen (Norway); Bjerknes Center for Climate Research, Bergen (Norway); University of Bergen, Geophysical Institute, Bergen (Norway); Nansen-Zhu International Research Center, Beijing (China)

    2009-02-15

    The response of the North Atlantic subpolar gyre (SPG) to a persistent positive (or negative) phase of the North Atlantic oscillation (NAO) is investigated using an ocean general circulation model forced with idealized atmospheric reanalysis fields. The integrations are analyzed with reference to a base-line integration for which the model is forced with idealized fields representing a neutral state of the NAO. In the positive NAO case, the results suggest that the well-known cooling and strengthening of the SPG are, after about 10 years, replaced by a warming and subsequent weakening of the SPG. The latter changes are caused by the advection of warm water from the subtropical gyre (STG) region, driven by a spin-up of the Atlantic meridional overturning circulation (AMOC) and the effect of an anomalous wind stress curl in the northeastern North Atlantic, which counteracts the local buoyancy forcing of the SPG. In the negative NAO case, however, the SPG response does not involve a sign reversal, but rather shows a gradual weakening throughout the integration. The asymmetric SPG-response to the sign of persistent NAO-like forcing and the different time scales involved demonstrate strong non-linearity in the North Atlantic Ocean circulation response to atmospheric forcing. The latter finding indicates that analysis based on the arithmetic difference between the two NAO-states, e.g. NAO+ minus NAO-, may hide important aspects of the ocean response to atmospheric forcing. (orig.)

  17. Ionospheric equatorial anomaly formation over Pacific and Atlantic oceans measured by NASA TOPEX satellite

    Energy Technology Data Exchange (ETDEWEB)

    Ewell, V.R.; Vladimer, J.A.; Lee, M.C. [Boston Univ., MA (United States). Electrical, Computer, and Systems Engineering Dept.; Doherty, P.H.; Decker, D.T. [Boston Coll., Newton, MA (United States). Inst. for Science Research; Anderson, D.N.; Klobuchar, J.A. [Phillips Lab., Hanscom AFB, MA (United States). Ionospheric Effects Branch

    1996-12-31

    Previous ionospheric observations have measured Total Electron Content (TEC) values at fixed land based locations. These observations suggest the existence of longitudinal variations in TEC values. Complementing ground data, the current NASA TOPEX mission is providing TEC data collected over oceans as a function of latitude, longitude and time starting from September 1992. With this broad data base, the authors show a more complete picture of the longitudinal dependence between the Atlantic and Pacific ocean regions and relate this dependence to plasma drifts. Periods during June and December solstice, and March and September equinox in the years 1992, through 1995, are picked to study the low-latitude regions spanning the Atlantic and Pacific oceans. TEC isodensity contours are presented by latitude versus longitude at common local time. They correlate these contours with results from the Phillips Laboratory ionospheric model.

  18. Little Ice Age wintertime climate cooling linked to N-Atlantic subpolar gyre warming

    Science.gov (United States)

    Kuijpers, Antoon; Seidenkrantz, Marit-Solveig; Sicre, Marie-Alexandrine; Andresen, Camilla S.; Staines-Urías, Francisca

    2015-04-01

    Traditionally, the Little Ice Age (LIA) in the North Atlantic is believed to have been marked by negative Sea Surface Temperature (SST) anomalies. In apparent contrast, we present evidence from sediment core records from the N-Atlantic Subpolar Gyre showing prevalence of warm SST conditions. Our proxy data include both alkenone-based SST reconstructions and results from faunal and geochemical foraminiferal studies. Subpolar Gyre SST warming after the Medieval Climate Anomaly is observed in the Labrador Current close to the Gulf Stream boundary off Newfoundland, which agrees with previously reported increased influence of warmer, Gulf Stream-derived Slope Water off southern Newfoundland(1). Our core records from the West- and East Greenland Current realm off southern Greenland, as well as sites in Faroese waters, correspondingly indicate increased influence of warm, saline North Atlantic / Irminger Current waters. Other recently published studies also report LIA SST warming in the northern subpolar North Atlantic(2) as well as increased heat transport into the Arctic via the West Spitsbergen Current(3). Growing evidence indicates that positive SST anomalies in the North Atlantic Ocean can promote negative NAO conditions, thus be linked with cold wintertime conditions in Northwestern Europe. A published modeling study using ensemble simulations with an atmospheric GCM forced with reconstructed SST data for the period 1871-1999 shows weakening of the westerly winds around 60o N with SST anomalies that have the same sign across the North Atlantic(4). Six other climate models show that with some years of delay, an intensified Atlantic Meridional Overturning Circulation leads to a weak negative North Atlantic Oscillation (NAO) phase during winter(5). Furthermore, it was recently found that the stratosphere is a key element of extra-tropical response to ocean variability. Observational analysis and atmospheric model experiments indicate that large-scale Atlantic Ocean

  19. "Ictal" lateralized periodic discharges.

    Science.gov (United States)

    Sen-Gupta, Indranil; Schuele, Stephan U; Macken, Micheal P; Kwasny, Mary J; Gerard, Elizabeth E

    2014-07-01

    Whether lateralized periodic discharges (LPDs) represent ictal or interictal phenomena, and even the circumstances in which they may represent one or the other, remains highly controversial. Lateralized periodic discharges are, however, widely accepted as being ictal when they are time-locked to clinically apparent symptoms. We sought to investigate the characteristics of "ictal" lateralized periodic discharges (ILPDs) defined by time-locked clinical symptoms in order to explore the utility of using this definition to dichotomize LPDs into "ictal" and "nonictal" categories. Our archive of all continuous EEG (cEEG) reports of adult inpatients undergoing prolonged EEG monitoring for nonelective indications between 2007 and 2011 was searched to identify all reports describing LPDs. Lateralized periodic discharges were considered ILPDs when they were reported as being consistently time-locked to clinical symptoms; LPDs lacking a clear time-locked correlate were considered to be "nonictal" lateralized periodic discharges (NILPDs). Patient charts and available neuroimaging studies were also reviewed. Neurophysiologic localization of LPDs, imaging findings, presence of seizures, discharge outcomes, and other demographic factors were compared between patients with ILPDs and those with NILPDs. p-Values were adjusted for false discovery rate (FDR). One thousand four hundred fifty-two patients underwent cEEG monitoring at our institution between 2007 and 2011. Lateralized periodic discharges were reported in 90 patients, 10 of whom met criteria for ILPDs. Nine of the patients with ILPDs demonstrated motor symptoms, and the remaining patient experienced stereotyped sensory symptoms. Ictal lateralized periodic discharges had significantly increased odds for involving central head regions (odds ratio [OR]=11; 95% confidence interval [CI]=2.16-62.6; p=0.018, FDR adjusted), with a trend towards higher proportion of lesions involving the primary sensorimotor cortex (p=0.09, FDR

  20. Puente Cañas

    OpenAIRE

    Luis Sáenz

    2017-01-01

    En la carretera de Trinidad a Cienfuegos, provincia de Las Villas (Cuba), se ha construido un puente isostático sobre el río Cañas, de hormigón pretensado, de tres tramos, cuya sección transversal es celular de tres tabiques formando un doble cajón. Los dos tramos laterales o accesos al central, de 15,5 m de luz cada uno, se han construido en voladizo respecto a los dos apoyos centrales. El tramo central salva un vano de 76 m.

  1. Puente Cañas

    Directory of Open Access Journals (Sweden)

    Luis Sáenz

    2017-05-01

    Full Text Available En la carretera de Trinidad a Cienfuegos, provincia de Las Villas (Cuba, se ha construido un puente isostático sobre el río Cañas, de hormigón pretensado, de tres tramos, cuya sección transversal es celular de tres tabiques formando un doble cajón. Los dos tramos laterales o accesos al central, de 15,5 m de luz cada uno, se han construido en voladizo respecto a los dos apoyos centrales. El tramo central salva un vano de 76 m.

  2. Glacial fluctuations of the Indian monsoon and their relationship with North Atlantic climate: new data and modelling experiments

    Directory of Open Access Journals (Sweden)

    C. Marzin

    2013-09-01

    Full Text Available Several paleoclimate records such as from Chinese loess, speleothems or upwelling indicators in marine sediments present large variations of the Asian monsoon system during the last glaciation. Here, we present a new record from the northern Andaman Sea (core MD77-176 which shows the variations of the hydrological cycle of the Bay of Bengal. The high-resolution record of surface water δ18O dominantly reflects salinity changes and displays large millennial-scale oscillations over the period 40 000 to 11 000 yr BP. Their timing and sequence suggests that events of high (resp. low salinity in the Bay of Bengal, i.e. weak (resp. strong Indian monsoon, correspond to cold (resp. warm events in the North Atlantic and Arctic, as documented by the Greenland ice core record. We use the IPSL_CM4 Atmosphere-Ocean coupled General Circulation Model to study the processes that could explain the teleconnection between the Indian monsoon and the North Atlantic climate. We first analyse a numerical experiment in which such a rapid event in the North Atlantic is obtained under glacial conditions by increasing the freshwater flux in the North Atlantic, which results in a reduction of the intensity of the Atlantic meridional overturning circulation. This freshwater hosing results in a weakening of the Indian monsoon rainfall and circulation. The changes in the continental runoff and local hydrological cycle are responsible for an increase in salinity in the Bay of Bengal. This therefore compares favourably with the new sea water δ18O record presented here and the hypothesis of synchronous cold North Atlantic and weak Indian monsoon events. Additional sensitivity experiments are produced with the LMDZ atmospheric model to analyse the teleconnection mechanisms between the North Atlantic and the Indian monsoon. The changes over the tropical Atlantic are shown to be essential in triggering perturbations of the subtropical jet over Africa and Eurasia, that in turn

  3. Modes of winter precipitation variability in the North Atlantic

    Energy Technology Data Exchange (ETDEWEB)

    Zorita, E. [GKSS-Forschungszentrum Geesthacht GmbH (Germany). Inst. fuer Hydrophysik; Saenz, J.; Fernandez, J.; Zubillaga, J. [Bilbao Univ. (Spain)

    2001-07-01

    The modes of variability of winter precipitation in the North Atlantic sector are identified by Empirical Orthogonal Functions Analysis in the NCEP/NCAR global reanalysis data sets. These modes are also present in a gridded precipitation data set over the Western Europe. The large-scale fields of atmospheric seasonal mean circulation, baroclinic activity, evaporation and humidity transport that are connected to the rainfall modes have been also analyzed in order to investigate the physical mechanisms that are causally linked to the rainfall modes. The results indicate that the leading rainfall mode is associated to the North Atlantic oscillation and represents a meridional redistribution of precipitation in the North Atlantic through displacements of the storm tracks. The second mode is related to evaporation anomalies in the Eastern Atlantic that precipitate almost entirely in the Western Atlantic. The third mode seems to be associated to meridional transport of water vapor from the Tropical Atlantic. (orig.)

  4. Displaced fracture through the anterior atlantal synchondrosis

    Energy Technology Data Exchange (ETDEWEB)

    Thakar, Chrishan; Allibone, James [Royal National Orthopaedic Hospital NHS Trust, Department of Spinal Deformity, Stanmore, Middlesex (United Kingdom); Harish, Srinivasan [Royal National Orthopaedic Hospital NHS Trust, Department of Radiology, Stanmore, Middlesex (United Kingdom); Saifuddin, Asif [Royal National Orthopaedic Hospital NHS Trust, Department of Radiology, Stanmore, Middlesex (United Kingdom); University College, The Institute of Orthopaedics and Musculoskeletal Sciences, London (United Kingdom)

    2005-09-01

    In the acute setting, accurate radiological interpretation of paediatric cervical spine trauma can be difficult due to a combination of normal variants and presence of multiple synchondroses. We present a rare case of a fracture through the anterior atlantal synchondrosis in a paediatric spine. A five-year-old boy, who fell backwards onto the top of his head while swinging across on a monkey bar frame, presented with neck pain, cervical muscle spasm and decreased right lateral rotation and extension of his neck. Computed tomography showed a displaced diastatic fracture through right anterior atlantal synchondrosis. There are only 12 cases of paediatric C1 fractures reported in the world literature. The importance of considering this diagnosis in the appropriate clinical setting, and the normal variants in the paediatric atlas that can cause diagnostic dilemma to the interpreting radiologist, are discussed in this case report. (orig.)

  5. Diagnosing overflow waters in the North Atlantic

    Science.gov (United States)

    Guo, Chuncheng; Ilicak, Mehmet; Bentsen, Mats; Fer, Ilker

    2015-04-01

    Danmark Strait overflow water (DSOW) and Iceland Faroe overflow water (ISOW) are important for the formation and transformation of deep waters in the North Atlantic. In this work the volume transport, variability, and pathways of DSOW and ISOW are diagnosed using the one degree ocean-ice coupled Norwegian Earth System Model (NorESM) that is forced by CORE2 inter-annual forcing. The oceanic component (MICOM) features an isopycnal coordinate that is referenced to 2000 db. The issues related to the coarse resolution such as the southward transport of ISOW to the western European Basin, the lack of overflow water in the western North Atlantic, and the western boundary detachment of the deep western boundary current are addressed. The effects of diapycnal mixing on the behavior of overflow descent at Denmark Strait and Faroe Bank Channel and its downstream evolution are examined.

  6. Operating in the North Atlantic MNPS Airspace

    Science.gov (United States)

    Whelan, Conor

    This paper considers the issue of operating aircraft through the North Atlantic's Minimum Navigation Performance Specification (MNPS) airspace. Noting that aircraft constantly strive for reduced fuel burn and uplift, it describes how flight operators and pilots conduct safe, efficient flights through the region. Reference is made to mechanisms of the North Atlantic MNPS airspace in terms of its Organized Track Structure and other routes that exist. These different structures emphasize the level of flexibility available. Flight planning procedures and requirements necessary to obtain oceanic Air Traffic Control (ATC) clearances are mentioned, as is an account of how communication and position reporting procedures operate to apply the Mach Number technique. Other aspects of MNPS operations such as ETOPS operational restrictions, meteorological effects, the employment of Reduced Vertical Separation Minima and planned regional changes aim to provide an overview of the MNPS system's current and future air traffic management.

  7. South Atlantic paleobathymetry since early Cretaceous.

    Science.gov (United States)

    Pérez-Díaz, Lucía; Eagles, Graeme

    2017-09-18

    We present early Cretaceous to present paleobathymetric reconstructions and quantitative uncertainty estimates for the South Atlantic, offering a strong basis for studies of paleocirculation, paleoclimate and paleobiogeography. Circulation in an initially salty and anoxic ocean, restricted by the topography of the Falkland Plateau, Rio Grande Ridge and Walvis Rise, favoured deposition of thick evaporites in shallow water of the Brazilian-Angolan margins. This ceased as seafloor spreading propagated northwards, opening an equatorial gateway to shallow and intermediate circulation. This gateway, together with subsiding volcano-tectonic barriers would have played a key role in Late Cretaceous climate changes. Later deepening and widening of the South Atlantic, together with gateway opening at Drake Passage would lead, by mid-Miocene (∼15 Ma) to the establishment of modern-style thermohaline circulation.

  8. Horizontal and vertical distribution of mesozooplankton species richness and composition down to 2,300 m in the southwest Atlantic Ocean

    Directory of Open Access Journals (Sweden)

    Sérgio L.C. Bonecker

    2014-10-01

    Full Text Available We describe the species richness, distribution and composition of mesozooplankton over the continental shelf and slope, and in the water masses in the Campos Basin, southwest Atlantic Ocean. We analyzed the mesozooplankton from two oceanographic cruises (rainy and dry seasons, 2009 with samples taken in five different water masses from the surface to 2,300 m depth. In the Subsurface Water (SS, in both sampling periods, more species were recorded over the slope (rainy: 100; dry: 128 than the continental shelf (rainy: 97; dry: 104. Over the slope, species richness decreased with increasing depth: the highest values were observed in the South Atlantic Central Water (SACW, and the lowest values in the North Atlantic Deep Water (NADW, in both sampling periods. We recorded 262 species in 10 groups (Hydrozoa, Siphonophora, Ctenophora, Branchiopoda, Copepoda, Euphausiacea, Decapoda, Chaetognatha, Appendicularia e Thaliacea, with 13 new occurrences for the southwest Atlantic. Copepoda was the group with the highest species richness, containing 138 species. In both periods, the samples from SS, SACW and Antarctic Intermediate Water (AAIW/Upper Circumpolar Deep Water (UCDW were clustered in different faunistic zones, based on species composition. This study confirmed that zooplankton richness in the southwest Atlantic Ocean is underestimated, and suggests that additional efforts must be directed toward a better understanding of this fairly unknown region.

  9. Copyright, Interfaces, and a Possible Atlantic Divide

    OpenAIRE

    Vezzoso, Simonetta

    2012-01-01

    Recent copyright cases on both sides of the Atlantic focused on important interoperability issues. While the decision by the Court of Justice of the European Union in SAS Institute, Inc.v. World Programming Ltd. assessed data formats under the EU Software Directive, the ruling by the Northern District of California Court in Oracle America, Inc. v. Google Inc. dealt with application programming interfaces. The European decision is rightly celebrated as a further important step in the promotion...

  10. Ballistic Missile Defense and the Atlantic Alliance

    OpenAIRE

    Yost, David S.

    1982-01-01

    T h e Atlantic Alliance may be at the threshold of a new debate on the implications of ballistic missile defense (BMD) for European security. Secretary of Defense Caspar Weinberger and several U.S. Senators and Congressmen support a thorough review of U.S. BMD options, including possible revision of the 1972 Anti- Ballistic Missile (ABM) Treaty and its 1974 Protocol. Although active defense of intercontinental ballistic missiles (ICBMs) seems the most likely application f...

  11. Prenatal nicotine and maternal deprivation stress de-regulate the development of CA1, CA3, and dentate gyrus neurons in hippocampus of infant rats.

    Directory of Open Access Journals (Sweden)

    Hong Wang

    Full Text Available Adverse experiences by the developing fetus and in early childhood are associated with profound effects on learning, emotional behavior, and cognition as a whole. In this study we investigated the effects of prenatal nicotine exposure (NIC, postnatal maternal deprivation (MD or the combination of the two (NIC+MD to determine if hippocampal neuron development is modulated by exposure to drugs of abuse and/or stress. Growth of rat offspring exposed to MD alone or NIC+MD was repressed until after weaning. In CA1 but not CA3 of postnatal day 14 (P14 pups, MD increased pyramidal neurons, however, in dentate gyrus (DG, decreased granule neurons. NIC had no effect on neuron number in CA1, CA3 or DG. Unexpectedly, NIC plus MD combined caused a synergistic increase in the number of CA1 or CA3 neurons. Neuron density in CA regions was unaffected by treatment, but in the DG, granule neurons had a looser packing density after NIC, MD or NIC+MD exposure. When septotemporal axes were analyzed, the synergism of stress and drug exposure in CA1 and CA3 was associated with rostral, whereas MD effects were predominantly associated with caudal neurons. TUNEL labeling suggests no active apoptosis at P14, and doublecortin positive neurons and mossy fibers were diminished in NIC+MD relative to controls. The laterality of the effect of nicotine and/or maternal deprivation in right versus left hippocampus was also analyzed and found to be insiginificant. We report for the first time that early life stressors such as postnatal MD and prenatal NIC exposure, when combined, may exhibit synergistic consequences for CA1 and CA3 pyramidal neuron development, and a potential antagonistic influence on developing DG neurons. These results suggest that early stressors may modulate neurogenesis, apoptosis, or maturation of glutamatergic neurons in the hippocampus in a region-specific manner during critical periods of neurodevelopment.

  12. Periodic Table of Students.

    Science.gov (United States)

    Johnson, Mike

    1998-01-01

    Presents an exercise in which an eighth-grade science teacher decorated the classroom with a periodic table of students. Student photographs were arranged according to similarities into vertical columns. Students were each assigned an atomic number according to their placement in the table. The table is then used to teach students about…

  13. Hereditary periodic fever syndromes

    NARCIS (Netherlands)

    McDermott, MF; Frenkel, J

    Hereditary periodic fever syndromes are defined by recurrent attacks of generalised inflammation for which no infectious or auto-immune cause can be identified. For most of these disorders, the molecular basis has recently been elucidated. This has opened the prospect of novel therapeutic

  14. Sawtooth Period Scaling

    CERN Document Server

    Connor, J W; Hastie, R J; Zocco, A

    2012-01-01

    We discuss the role of neoclassical resistivity and local magnetic shear in the prediction of the sawtooth period in tokamaks. When collisional detrapping of electrons is considered the value of the safety factor on axis, $q(t,0)$, evolves on a new time scale, $\\tau_{*}=\\tau_{\\eta}\

  15. Modelling the future biogeography of North Atlantic zooplankton communities in response to climate change

    KAUST Repository

    Villarino, E

    2015-07-02

    Advances in habitat and climate modelling allow us to reduce uncertainties of climate change impacts on species distribution. We evaluated the impacts of future climate change on community structure, diversity, distribution and phenology of 14 copepod species in the North Atlantic. We developed and validated habitat models for key zooplankton species using continuous plankton recorder (CPR) survey data collected at mid latitudes of the North Atlantic. Generalized additive models (GAMs) were applied to relate the occurrence of species to environmental variables. Models were projected to future (2080–2099) environmental conditions using coupled hydroclimatix–biogeochemical models under the Intergovernmental Panel on Climate Change (IPCC) A1B climate scenario, and compared to present (2001–2020) conditions. Our projections indicated that the copepod community is expected to respond substantially to climate change: a mean poleward latitudinal shift of 8.7 km per decade for the overall community with an important species range variation (–15 to 18 km per decade); the species seasonal peak is expected to occur 12–13 d earlier for Calanus finmarchicus and C. hyperboreus; and important changes in community structure are also expected (high species turnover of 43–79% south of the Oceanic Polar Front). The impacts of the change expected by the end of the century under IPCC global warming scenarios on copepods highlight poleward shifts, earlier seasonal peak and changes in biodiversity spatial patterns that might lead to alterations of the future North Atlantic pelagic ecosystem. Our model and projections are supported by a temporal validation undertaken using the North Atlantic climate regime shift that occurred in the 1980s: the habitat model built in the cold period (1970–1986) has been validated in the warm period (1987–2004).

  16. Bathymetric controls on Pliocene North Atlantic and Arctic sea surface temperature and deepwater production

    Science.gov (United States)

    Robinson, M.M.; Valdes, P.J.; Haywood, A.M.; Dowsett, H.J.; Hill, D.J.; Jones, S.M.

    2011-01-01

    The mid-Pliocene warm period (MPWP; ~. 3.3 to 3.0. Ma) is the most recent interval in Earth's history in which global temperatures reached and remained at levels similar to those projected for the near future. The distribution of global warmth, however, was different than today in that the high latitudes warmed more than the tropics. Multiple temperature proxies indicate significant sea surface warming in the North Atlantic and Arctic Oceans during the MPWP, but predictions from a fully coupled ocean-atmosphere model (HadCM3) have so far been unable to fully predict the large scale of sea surface warming in the high latitudes. If climate proxies accurately represent Pliocene conditions, and if no weakness exists in the physics of the model, then model boundary conditions may be in error. Here we alter a single boundary condition (bathymetry) to examine if Pliocene high latitude warming was aided by an increase in poleward heat transport due to changes in the subsidence of North Atlantic Ocean ridges. We find an increase in both Arctic sea surface temperature and deepwater production in model experiments that incorporate a deepened Greenland-Scotland Ridge. These results offer both a mechanism for the warming in the North Atlantic and Arctic Oceans indicated by numerous proxies and an explanation for the apparent disparity between proxy data and model simulations of Pliocene northern North Atlantic and Arctic Ocean conditions. Determining the causes of Pliocene warmth remains critical to fully understanding comparisons of the Pliocene warm period to possible future climate change scenarios. ?? 2011.

  17. Use of otolith strontium:calcium and zinc:calcium ratios as an indicator of the habitat of Percophis brasiliensis Quoy & Gaimard, 1825 in the southwestern Atlantic Ocean

    Directory of Open Access Journals (Sweden)

    Esteban Avigliano

    Full Text Available We evaluate the simultaneous use of Sr: Ca and Zn: Ca ratios of the sagitta otolith as a potential indicator of the habitat of Percophis brasiliensis along a latitudinal gradient in the southwestern Atlantic Ocean (34-42ºS and 51-67ºW, in order to reliably identify fish stocks. Fish were collected in three sampling sites: Argentine-Uruguayan Common Fishing Zone (AUCFZ, El Rincón (ER and San Matías Gulf (SMG. The otolith Sr:Ca and Zn:Ca ratios were determined by ICP-OES and EDTA volumetric method. The otolith Sr:Ca ratio was similar in the three sampling sites, while the Zn:Ca ratio was significantly higher in AUCFZ than in ER and SMG for all age groups. The discriminant analysis showed an association between the otolith Sr:Ca and Zn:Ca ratios from ER and SMG. Present results suggest the potential occurrence of two fish stocks of P. brasiliensis in the study area.

  18. NEFSC 2000 Atlantic Herring Acoustic/Midwater Trawl Survey (DE0008, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC Atlantic herring acoustic survey is a fisheries independent survey that provides scientific data for Atlantic herring assessments in the U.S. mid-Atlantic...

  19. NEFSC 1999 Atlantic Herring Acoustic/Midwater Trawl Survey (DE9909, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC Atlantic herring acoustic survey is a fisheries independent survey that provides scientific data for Atlantic herring assessments in the U.S. mid-Atlantic...

  20. NEFSC 2004 Atlantic Herring Acoustic/Midwater Trawl Survey (DE0413, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC Atlantic herring acoustic survey is a fisheries independent survey that provides scientific data for Atlantic herring assessments in the U.S. mid-Atlantic...

  1. NEFSC 2008 Atlantic Herring Acoustic/Midwater Trawl Survey (DE0809, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC Atlantic herring acoustic survey is a fisheries independent survey that provides scientific data for Atlantic herring assessments in the U.S. mid-Atlantic...

  2. NEFSC 2012 Atlantic Herring Acoustic/Midwater Trawl Survey (PC1206, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC Atlantic herring acoustic survey is a fisheries independent survey that provides scientific data for Atlantic herring assessments in the U.S. mid-Atlantic...

  3. NEFSC 1998 Atlantic Herring Acoustic/Midwater Trawl Survey (DE9810, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC Atlantic herring acoustic survey is a fisheries independent survey that provides scientific data for Atlantic herring assessments in the U.S. mid-Atlantic...

  4. NEFSC 2009 Atlantic Herring Acoustic/Midwater Trawl Survey (DE0910, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC Atlantic herring acoustic survey is a fisheries independent survey that provides scientific data for Atlantic herring assessments in the U.S. mid-Atlantic...

  5. NEFSC 2011 Atlantic Herring Acoustic/Midwater Trawl Survey (DE1108, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC Atlantic herring acoustic survey is a fisheries independent survey that provides scientific data for Atlantic herring assessments in the U.S. mid-Atlantic...

  6. NEFSC 2005 Atlantic Herring Acoustic/Midwater Trawl Survey (DE0512, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC Atlantic herring acoustic survey is a fisheries independent survey that provides scientific data for Atlantic herring assessments in the U.S. mid-Atlantic...

  7. NEFSC 2010 Atlantic Herring Acoustic/Midwater Trawl Survey (DE1010, EK60)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC Atlantic herring acoustic survey is a fisheries independent survey that provides scientific data for Atlantic herring assessments in the U.S. mid-Atlantic...

  8. NEFSC 2001 Atlantic Herring Acoustic/Midwater Trawl Survey (DE0109, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC Atlantic herring acoustic survey is a fisheries independent survey that provides scientific data for Atlantic herring assessments in the U.S. mid-Atlantic...

  9. NEFSC 2002 Atlantic Herring Acoustic/Midwater Trawl Survey (DE0208, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC Atlantic herring acoustic survey is a fisheries independent survey that provides scientific data for Atlantic herring assessments in the U.S. mid-Atlantic...

  10. NEFSC 2003 Atlantic Herring Acoustic/Midwater Trawl Survey (DE0308, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC Atlantic herring acoustic survey is a fisheries independent survey that provides scientific data for Atlantic herring assessments in the U.S. mid-Atlantic...

  11. NEFSC 2007 Atlantic Herring Acoustic/Midwater Trawl Survey (DE0710, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC Atlantic herring acoustic survey is a fisheries independent survey that provides scientific data for Atlantic herring assessments in the U.S. mid-Atlantic...

  12. 78 FR 3401 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Science.gov (United States)

    2013-01-16

    ...; Atlantic Mackerel, Squid, and Butterfish Fisheries; Scoping Process; Mid-Atlantic Fishery Management... support for an amendment (Amendment 16) to the Fishery Management Plan (FMP) for Atlantic Mackerel, Squid...

  13. NEFSC 2006 Atlantic Herring Acoustic/Midwater Trawl Survey (DE0615, EK500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NEFSC Atlantic herring acoustic survey is a fisheries independent survey that provides scientific data for Atlantic herring assessments in the U.S. mid-Atlantic...

  14. Sound Speed Structure of the Western South Atlantic Ocean.

    Science.gov (United States)

    1982-07-01

    for the western South Atlantic between 9°S and 36°S latitude and for the entire western South Atlantic by Buscaglia (1971). All these sources...both the Brazil Plain and Argentine Plain. Similar perturbations are also evident along winter cross-section A. As noted by Buscaglia (1971), the top...Duedall and Coote (1972) and throughout the western South Atlantic Ocean by Buscaglia (1971). In the presence of this intermixing, the MIW sound speed

  15. Ocean Modeling of the North Atlantic

    Science.gov (United States)

    Seminar, A. J.

    1984-01-01

    Present modeling of the North Atlantic is inadequate and can be improved in a number of ways. A number of important physical processes are listed in five categories from the viewpoints of how they are treated in isolation, how they are usually represented in present ocean basin models, and how they may be better represented in future models. In the first two categories of vertical boundary processes and internal vertical mixing, parameterizations exist which can easily be incorporated into models and which will have important effects on the simulated structure of the North Atlantic. For the third catagory (mesoscale eddy effects), adequate parameterizations do not exist; but the order of magnitude of the effects is known from observational and process-model studies. A horizontal grid spacing of 100 km or less in required to allow parameterizations with this order of magnitude, as well as to resolve the time-averaged ocean fields. In the fourth category of large scale transports improvements are suggested by way of increased vertical resolution and by the requirement that lateral mixing due to eddies takes place on isopycnal surfaces. Model incorporation of the latter phenomenta is underway. In the fifth category of miscellaneous high-latitude processes, formulations for the treatment of sea ice are available for use. However, the treatment of gravitational instability, which is crucial to deepwater formation in the Atlantic Ocean, will require additional refinements to account for the unresolved physics of chimney formations in the open ocean and buoyant plumes near ocean boundaries.

  16. Atlantic and indian oceans pollution in africa

    Science.gov (United States)

    Abubakar, Babagana

    Africa is the second largest and most populated continent after Asia. Geographically it is located between the Atlantic and Indian Oceans. Most of the Africa's most populated and industrialized cities are located along the coast of the continent facing the Atlantic and Indian Oceans, example of such cities include Casablanca, Dakar, Accra, Lagos, Luanda and Cape town all facing the Atlantic Ocean and cities like East London, Durban, Maputo, Dar-es-salaam and Mogadishu are all facing the Indian Ocean. As a result of the geographical locations of African Coastal Cities plus increase in their population, industries, sea port operations, petroleum exploration activities, trafficking of toxic wastes and improper waste management culture lead to the incessant increase in the pollution of the two oceans. NATURE OF POLLUTION OF THE ATLANTIC OCEAN i. The petroleum exploration activities going on along the coast of "Gulf of Guinea" region and Angola continuously causes oil spillages in the process of drilling, bunkering and discharging of petroleum products in the Atlantic Ocean. ii. The incessant degreasing of the Sea Ports "Quay Aprons" along the Coastal cities of Lagos, Luanda, Cape Town etc are continuously polluting the Atlantic Ocean with chemicals. iii. Local wastes generated from the houses located in the coastal cities are always finding their ways into the Atlantic Ocean. NATURE OF POLLUTION OF THE INDIAN OCEAN i. Unlike the Atlantic ocean where petroleum is the major pollutant, the Indian Ocean is polluted by Toxic / Radioactive waste suspected to have been coming from the developed nations as reported by the United Nations Environmental Programme after the Tsunami disaster in December 2004 especially along the coast of Somalia. ii. The degreasing of the Quay Aprons at Port Elizabeth, Maputo, Dar-es-Salaam and Mongolism Sea Ports are also another major source polluting the Indian Ocean. PROBLEMS GENERATED AS A RESULT OF THE OCEANS POLLUTION i. Recent report

  17. Novel Ca2+ increases in the maturing oocytes of starfish during the germinal vesicle breakdown.

    Science.gov (United States)

    Limatola, Nunzia; Chun, Jong T; Kyozuka, Keiichiro; Santella, Luigia

    2015-11-01

    after the hormone-dependent period, LAT-A inhibited the occurrence (frequency) of the spikes in a dose-dependent manner, but the amplitude of the prevailing Ca(2+) spikes itself was rather significantly increased. These results suggest that the cortical actin cytoskeleton and some nuclear factors may play a role in regulating ion channel activities during this stage of meiotic progression. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Residency, site fidelity and habitat use of Atlantic cod (Gadus morhua) at an offshore wind farm using acoustic telemetry.

    Science.gov (United States)

    Reubens, Jan T; Pasotti, Francesca; Degraer, Steven; Vincx, Magda

    2013-09-01

    Because offshore wind energy development is fast growing in Europe it is important to investigate the changes in the marine environment and how these may influence local biodiversity and ecosystem functioning. One of the species affected by these ecosystem changes is Atlantic cod (Gadus morhua), a heavily exploited, commercially important fish species. In this research we investigated the residency, site fidelity and habitat use of Atlantic cod on a temporal scale at windmill artificial reefs in the Belgian part of the North Sea. Acoustic telemetry was used and the Vemco VR2W position system was deployed to quantify the movement behaviour. In total, 22 Atlantic cod were tagged and monitored for up to one year. Many fish were present near the artificial reefs during summer and autumn, and demonstrated strong residency and high individual detection rates. When present within the study area, Atlantic cod also showed distinct habitat selectivity. We identified aggregation near the artificial hard substrates of the wind turbines. In addition, a clear seasonal pattern in presence was observed. The high number of fish present in summer and autumn alternated with a period of very low densities during the winter period. Copyright © 2013 Elsevier Ltd. All rights reserved.

  19. Multiple Ca2+ sensors in secretion

    DEFF Research Database (Denmark)

    Walter, Alexander M; Groffen, Alexander J; Sørensen, Jakob Balslev

    2011-01-01

    Regulated neurotransmitter secretion depends on Ca(2+) sensors, C2 domain proteins that associate with phospholipids and soluble N-ethylmaleimide-sensitive fusion attachment protein receptor (SNARE) complexes to trigger release upon Ca(2+) binding. Ca(2+) sensors are thought to prevent spontaneous...... fusion at rest (clamping) and to promote fusion upon Ca(2+) activation. At least eight, often coexpressed, Ca(2+) sensors have been identified in mammals. Accumulating evidence suggests that multiple Ca(2+) sensors interact, rather than work autonomously, to produce the complex secretory response...... observed in neurons and secretory cells. In this review, we present several working models to describe how different sensors might be arranged to mediate synchronous, asynchronous and spontaneous neurotransmitter release. We discuss the scenario that different Ca(2+) sensors typically act on one shared...

  20. The early Holocene humid period in the Tayma palaeolake, NW Arabian Peninsula -- A high-resolution micro-facies and geochemical approach

    Science.gov (United States)

    Neugebauer, Ina; Plessen, Birgit; Dinies, Michèle; Engel, Max; Tjallingii, Rik; Brauer, Achim

    2016-04-01

    The Tayma palaeolake is a rare archive of the early Holocene humid period in northern Arabia (Dinies et al. 2015; Engel et al. 2012). Here we present a ca. 1 m thick and 500 years spanning annually laminated sediment section that was deposited in the centre of the former lake from ca. 8500 to 8000 calibrated years (cal. yrs) BP, as determined by AMS 14C dating of pollen concentrates (Dinies et al. 2015). High-resolution micro-facies analyses based on thin section microscopy, μXRF element scanning, δ18Ocarb and δ13Ccarb measurements on single carbonate laminae, as well as geochemical measurements on bulk samples for TOC, CaCO3, C/N ratio, δ18Ocarb, δ13Ccarb, δ13Corg and δ15N determination were performed in order to investigate the sedimentological and geochemical changes along the varved sequence in great detail. The finely laminated marl sediments are mainly composed of sub-mm thick laminae of endogenic aragonite, organic matter and diatoms, as well as occasional, often graded silt-clay layers. Following an early lake phase from ca. 8700 to 8500 cal. yrs BP characterized by coarsely laminated, presumably non-annual marl sediments that are rich in ostracods, three main varved phases can be distinguished within the investigated section: (1) aragonitic-organic varves from ca. 8500 to 8300 cal. yrs BP, (2) diatom-organic varves from ca. 8300 to 8100 cal. yrs BP that frequently include aragonite laminae and occasionally gastropod and ostracod shells, and (3) organic varves from ca. 8100 to 8000 cal. yrs BP with decreasing diatom and aragonite laminae and an increasing frequency of gypsum layers. After this period, gypsum becomes abundant and fine lamination appears only sporadically. In addition, we observe increasing trends of TOC, C/N and δ13Ccarb and decreasing δ18Ocarb during phase 1 and excess δ18Ocarb, δ13Ccarb and TOC values during phase 2, pointing towards the maximum lake productivity and increased seasonal precipitation. We interpret this

  1. Retrospective analysis of seasonal ocean growth rates of two sea winter Atlantic Salmon in eastern Maine using historic scales

    Science.gov (United States)

    Izzo, Lisa K.; Zydlewski, Joseph D.

    2017-01-01

    Substantial declines of anadromous Atlantic Salmon Salmo salar have occurred throughout its range, with many populations at the southern extent of the distribution currently extirpated or endangered. While both one sea winter (1SW) and two sea winter (2SW) spawner numbers for the North American stocks have declined since the 1950s, the decline has been most severe in 2SW spawners. The first months at sea are considered a period of high mortality. However, early ocean mortality alone cannot explain the more pronounced decline of 2SW spawners, suggesting that the second year at sea may be more critical than previously thought. Atlantic Salmon scales collected by anglers and the state agency from 1946 to 2013 from five rivers in eastern Maine were used to estimate smolt age and ocean age of returning adults. Additionally, seasonal growth rates of maiden 2SW spawners were estimated using intercirculi measurements and linear back-calculation methods. Generalized linear mixed models (Gaussian family, log link function) were used to investigate the influence of average sea surface temperature, accumulated thermal units, the Atlantic Multidecadal Oscillation (AMO) and North Atlantic Oscillation indices, smolt age, smolt length, postsmolt growth, and river of origin on growth rate during the oceanic migration of North American Atlantic Salmon. Results suggest that different factors influence salmon growth throughout their oceanic migration, and previous growth can be a strong predictor of future size. Growth was negatively impacted by the phase of the AMO, which has been linked to salmon abundance trends, in early spring following the postsmolt period. This is likely when the 1SW and 2SW stock components separate, and our results suggest that this period may be of interest in future work examining the disproportionate decline in 2SW spawners.

  2. Diet, feeding patterns, and prey selection of subyearling Atlantic salmon (Salmo salar) and subyearling chinook salmon (Oncorhynchus tshawytscha) in a tributary of Lake Ontario

    Science.gov (United States)

    Johnson, J. H.; Nash, K. J.; Chiavelli, R. A.; DiRado, J. A.; Mackey, G. E.; Knight, J. R.; Diaz, A. R.

    2017-01-01

    Since juvenile Atlantic salmon (Salmo salar) and Chinook salmon (Oncorhynchus tshawytscha) occupy a similar habitat in Lake Ontario tributaries, we sought to determine the degree of diet similarity between these species in order to assess the potential for interspecific competition. Atlantic salmon, an historically important but currently extirpated component of the Lake Ontario fish community, are the focus of a bi-national restoration effort. Presently this effort includes the release of hatchery produced juvenile Atlantic salmon in Lake Ontario tributaries. These same tributaries support substantial numbers of naturally reproduced juvenile Pacific salmonids including Chinook salmon. Subyearling Atlantic salmon and subyearling Chinook salmon had significantly different diets during each of the three time periods examined. Atlantic salmon fed slightly more from the benthos than from the drift and consumed mainly chirononmids (47.0%) and ephemeropterans (21.1%). The diet of subyearling Chinook salmon was more closely associated with the drift and consisted mainly of chironomids (60.2%) and terrestrial invertebrates (16.0%). Low diet similarity between subyearling Atlantic salmon and subyearling Chinook salmon likely minimizes competitive interactions for food between these species in Lake Ontario tributaries. However, the availability of small prey such as chironomids which comprise over 50% of the diet of each species, soon after emergence, could constitute a short term resource limitation. To our knowledge this is the first study of interspecific diet associations between these two important salmonid species.

  3. Understanding and simulating the link between African easterly waves and Atlantic tropical cyclones using a regional climate model: the role of domain size and lateral boundary conditions

    Energy Technology Data Exchange (ETDEWEB)

    Caron, Louis-Philippe [MISU, Stockholm University, Stockholm (Sweden); Universite du Quebec a Montreal, CRCMD Network, Montreal, QC (Canada); Jones, Colin G. [Swedish Meterological and Hydrological Institute, Rossby Center, Norrkoeping (Sweden)

    2012-07-15

    Using a suite of lateral boundary conditions, we investigate the impact of domain size and boundary conditions on the Atlantic tropical cyclone and african easterly Wave activity simulated by a regional climate model. Irrespective of boundary conditions, simulations closest to observed climatology are obtained using a domain covering both the entire tropical Atlantic and northern African region. There is a clear degradation when the high-resolution model domain is diminished to cover only part of the African continent or only the tropical Atlantic. This is found to be the result of biases in the boundary data, which for the smaller domains, have a large impact on TC activity. In this series of simulations, the large-scale Atlantic atmospheric environment appears to be the primary control on simulated TC activity. Weaker wave activity is usually accompanied by a shift in cyclogenesis location, from the MDR to the subtropics. All ERA40-driven integrations manage to capture the observed interannual variability and to reproduce most of the upward trend in tropical cyclone activity observed during that period. When driven by low-resolution global climate model (GCM) integrations, the regional climate model captures interannual variability (albeit with lower correlation coefficients) only if tropical cyclones form in sufficient numbers in the main development region. However, all GCM-driven integrations fail to capture the upward trend in Atlantic tropical cyclone activity. In most integrations, variations in Atlantic tropical cyclone activity appear uncorrelated with variations in African easterly wave activity. (orig.)

  4. Non–Ca2+-conducting Ca2+ channels in fish skeletal muscle excitation-contraction coupling

    Science.gov (United States)

    Schredelseker, Johann; Shrivastav, Manisha; Dayal, Anamika; Grabner, Manfred

    2010-01-01

    During skeletal muscle excitation-contraction (EC) coupling, membrane depolarizations activate the sarcolemmal voltage-gated L-type Ca2+ channel (CaV1.1). CaV1.1 in turn triggers opening of the sarcoplasmic Ca2+ release channel (RyR1) via interchannel protein–protein interaction to release Ca2+ for myofibril contraction. Simultaneously to this EC coupling process, a small and slowly activating Ca2+ inward current through CaV1.1 is found in mammalian skeletal myotubes. The role of this Ca2+ influx, which is not immediately required for EC coupling, is still enigmatic. Interestingly, whole-cell patch clamp experiments on freshly dissociated skeletal muscle myotubes from zebrafish larvae revealed the lack of such Ca2+ currents. We identified two distinct isoforms of the pore-forming CaV1.1α1S subunit in zebrafish that are differentially expressed in superficial slow and deep fast musculature. Both do not conduct Ca2+ but merely act as voltage sensors to trigger opening of two likewise tissue-specific isoforms of RyR1. We further show that non-Ca2+ conductivity of both CaV1.1α1S isoforms is a common trait of all higher teleosts. This non-Ca2+ conductivity of CaV1.1 positions teleosts at the most-derived position of an evolutionary trajectory. Though EC coupling in early chordate muscles is activated by the influx of extracellular Ca2+, it evolved toward CaV1.1-RyR1 protein–protein interaction with a relatively small and slow influx of external Ca2+ in tetrapods. Finally, the CaV1.1 Ca2+ influx was completely eliminated in higher teleost fishes. PMID:20212109

  5. Temporal monitoring of intracellular Ca2+ signaling and origins of Ca2+ oscillations

    OpenAIRE

    Webb, Dominic-Luc

    2006-01-01

    This thesis examined parameters influencing stimulated cytoplasmic free Ca2+ concentration ([Ca2+]i) oscillations in hepatocytes and pancreatic beta-cells. Hepatic glucose output is regulated in part by hormones such as vasopressin that act through [Ca 2+]i oscillations. Pulsatile [Ca2+]i in beta-cells parallels insulin secretion and this results in potently controlled blood glucose homeostasis. Employing temporal [Ca2+]i measurements and related biochemical assays, efforts ...

  6. Effects of hexazinone and atrazine on the physiology and endocrinology of smolt development in Atlantic salmon

    Science.gov (United States)

    Nieves-Puigdoller, K.; Bjornsson, Bjorn Thrandur; McCormick, S.D.

    2007-01-01

    Exposure to hexazinone (HEX) and atrazine (ATZ), highly mobile and widely used herbicides along rivers in the United States, is potentially harmful to Atlantic salmon, which have been listed as an endangered species. To determine the effects of these contaminants on smolt development, juvenile Atlantic salmon were exposed under flow-through conditions to 100 ??g l-1 HEX, 10 and 100 ??g l-1 ATZ in fresh water (FW) for 21 days at 10 ??C beginning in mid-April. Twelve fish per treatment were sampled in FW, following a 24 h seawater (SW) challenge and after growth for 3 months in SW. Exposure to 100 ??g l-1 HEX or 10 ??g l-1 ATZ caused no mortalities of smolts in FW or after SW challenge, while 9% of the fish exposed to 100 ??g l-1 ATZ died during exposure. Fish exposed to 100 ??g l-1 ATZ reduced feeding after 10 days of exposure and had an impaired growth rate in FW and during the first month in SW; compensatory growth occurred in the second and third month in SW. HEX and ATZ at 10 ??g l-1 exposure had no effect on plasma levels of cortisol, growth hormone (GH), insulin growth factor I (IGF-I), thyroxine (T4) and plasma 3,5,3???-triiodo-l-thyronine (T3), Cl-, Mg2+, Na+, Ca2+ in FW or after SW challenge. FW smolts exposed to 100 ??g l-1 ATZ had decreased plasma Cl-, Mg2+, Na+ and Ca2+ ions and increased cortisol. No effect on plasma levels of GH, IGF-I, T4 or T3 was found in FW smolts exposed to 100 ??g l-1 ATZ. Following SW challenge, fish previously exposed to 100 ??g l-1 ATZ had significant increases in hematocrit, plasma cortisol, Cl-, Mg2+, Na+, Ca2+ and a decrease in T4 and T3. It is concluded that under the conditions imposed in this study, HEX does not affect salinity tolerance of Atlantic salmon smolts, while ATZ causes ionoregulatory, growth and endocrine disturbance. ?? 2007 Elsevier B.V. All rights reserved.

  7. CARINA oxygen data in the Atlantic Ocean

    Directory of Open Access Journals (Sweden)

    I. Stendardo

    2009-12-01

    Full Text Available In the CARINA (Carbon dioxide in the Atlantic Ocean project, a new dataset with many previously unpublished hydrographic data from the Atlantic, Arctic and Southern Ocean was assembled and subjected to careful quality control (QC procedures. Here, we present the dissolved oxygen measurements in the Atlantic region of the dataset and describe in detail the secondary QC procedures that aim to ensure that the data are internally consistent. This is achieved by a cross-over analysis, i.e. the comparison of deep ocean data at places that were sampled by different cruises at different times. Initial adjustments to the individual cruises were then determined by an inverse procedure that computes a set of adjustments that requires the minimum amount of adjustment and at the same time reduces the offsets in an optimal manner. The initial adjustments were then reviewed by the CARINA members, and only those that passed the following two criteria were adopted: (i the region is not subject to substantial temporal variability, and (ii the adjustment must be based on at least three stations from each cruise. No adjustment was recommended for cruises that did not fit these criteria. The final CARINA-Oxygen dataset has 103414 oxygen samples from 9491 stations obtained during 98 cruises covering three decades. The sampling density of the oxygen data is particularly good in the North Atlantic north of about 40° N especially after 1987. In contrast, the sample density in the South Atlantic is much lower. Some cruises appear to have poor data quality, and were subsequently omitted from the adjusted dataset. Of the data included in the adjusted dataset, 20% were adjusted with a mean adjustment of 2%. Due to the achieved internal consistency, the resulting product is well suited to produce an improved climatology or to study long-term changes in the oxygen content of the ocean. However, the adjusted dataset is not necessarily better suited than the unadjusted data to

  8. Atlantic water flow through the Faroese Channels

    Directory of Open Access Journals (Sweden)

    B. Hansen

    2017-11-01

    Full Text Available Through the Faroese Channels – the collective name for a system of channels linking the Faroe–Shetland Channel, Wyville Thomson Basin, and Faroe Bank Channel – there is a deep flow of cold waters from Arctic regions that exit the system as overflow through the Faroe Bank Channel and across the Wyville Thomson Ridge. The upper layers, in contrast, are dominated by warm, saline water masses from the southwest, termed Atlantic water. In spite of intensive research over more than a century, there are still open questions on the passage of these waters through the system with conflicting views in recent literature. Of special note is the suggestion that there is a flow of Atlantic water from the Faroe–Shetland Channel through the Faroe Bank Channel, which circles the Faroes over the slope region in a clockwise direction. Here, we combine the observational evidence from ship-borne hydrography, moored current measurements, surface drifter tracks, and satellite altimetry to address these questions and propose a general scheme for the Atlantic water flow through this channel system. We find no evidence for a continuous flow of Atlantic water from the Faroe–Shetland Channel to the Faroe Bank Channel over the Faroese slope. Rather, the southwestward-flowing water over the Faroese slope of the Faroe–Shetland Channel is totally recirculated within the combined area of the Faroe–Shetland Channel and Wyville Thomson Basin, except possibly for a small release in the form of eddies. This does not exclude a possible westward flow over the southern tip of the Faroe Shelf, but even including that, we estimate that the average volume transport of a Circum-Faroe Current does not exceed 0.5 Sv (1 Sv  =  106 m3 s−1. Also, there seems to be a persistent flow of Atlantic water from the western part of the Faroe Bank Channel into the Faroe–Shetland Channel that joins the Slope Current over the Scottish slope. These conclusions will affect

  9. Atlantic water flow through the Faroese Channels

    Science.gov (United States)

    Hansen, Bogi; Poulsen, Turið; Margretha Húsgarð Larsen, Karin; Hátún, Hjálmar; Østerhus, Svein; Darelius, Elin; Berx, Barbara; Quadfasel, Detlef; Jochumsen, Kerstin

    2017-11-01

    Through the Faroese Channels - the collective name for a system of channels linking the Faroe-Shetland Channel, Wyville Thomson Basin, and Faroe Bank Channel - there is a deep flow of cold waters from Arctic regions that exit the system as overflow through the Faroe Bank Channel and across the Wyville Thomson Ridge. The upper layers, in contrast, are dominated by warm, saline water masses from the southwest, termed Atlantic water. In spite of intensive research over more than a century, there are still open questions on the passage of these waters through the system with conflicting views in recent literature. Of special note is the suggestion that there is a flow of Atlantic water from the Faroe-Shetland Channel through the Faroe Bank Channel, which circles the Faroes over the slope region in a clockwise direction. Here, we combine the observational evidence from ship-borne hydrography, moored current measurements, surface drifter tracks, and satellite altimetry to address these questions and propose a general scheme for the Atlantic water flow through this channel system. We find no evidence for a continuous flow of Atlantic water from the Faroe-Shetland Channel to the Faroe Bank Channel over the Faroese slope. Rather, the southwestward-flowing water over the Faroese slope of the Faroe-Shetland Channel is totally recirculated within the combined area of the Faroe-Shetland Channel and Wyville Thomson Basin, except possibly for a small release in the form of eddies. This does not exclude a possible westward flow over the southern tip of the Faroe Shelf, but even including that, we estimate that the average volume transport of a Circum-Faroe Current does not exceed 0.5 Sv (1 Sv = 106 m3 s-1). Also, there seems to be a persistent flow of Atlantic water from the western part of the Faroe Bank Channel into the Faroe-Shetland Channel that joins the Slope Current over the Scottish slope. These conclusions will affect potential impacts from offshore activities in the

  10. Biocompatibility and strength retention of biodegradable Mg-Ca-Zn alloy bone implants.

    Science.gov (United States)

    Cho, Sung Youn; Chae, Soo-Won; Choi, Kui Won; Seok, Hyun Kwang; Kim, Yu Chan; Jung, Jae Young; Yang, Seok Jo; Kwon, Gyeong Je; Kim, Jong Tack; Assad, Michel

    2013-02-01

    The biocompatibility and strength retention of a Mg-Ca-Zn alloy were studied to evaluate its efficacy for osteosynthesis applications. Mg-Ca-Zn alloy and self-reinforced poly l-lactide (SR-PLLA) bone screws were implanted into New Zealand rabbits for radiography analysis, micro computed tomography analysis, histomorphometry, hematology, serum biochemistry, histopathology, and inductively coupled plasma mass spectrometry analysis. Bending and torsion tests were performed on intact specimens to find the initial mechanical strength of these Mg-Ca-Zn alloy bone screws. Strength retention of the Mg-Ca-Zn alloy implants were calculated from in vivo degradation rates and initial mechanical strength. Based on the animal study, Mg-Ca-Zn alloy bone screw showed absence of subcutaneous gas pockets, characteristic surface erosion properties, faster degradation rate than SR-PLLA bone screw, normal reference range of hematology and serum biochemistry, better histopathological response than SR-PLLA bone screw, and stable concentrations of each constituent element in soft tissues surrounding the implants. The initial strength and strength retention of Mg-Ca-Zn alloy were compared with those of various biomaterials. The initial strength of Mg-Ca-Zn alloy was higher than those of biostable and biodegradable polymers. The strength retention of Mg-Ca-Zn alloy bone screws was similar to those of biodegradable polymer. Therefore, this Mg-Ca-Zn alloy represents an excellent biodegradable biomaterial candidate for osteosynthesis applications. Copyright © 2012 Wiley Periodicals, Inc.

  11. 75 FR 4348 - Mid-Atlantic Fishery Management Council; Public Hearings

    Science.gov (United States)

    2010-01-27

    .... ADDRESSES: Send comments to: Daniel T. Furlong, Executive Director, Mid-Atlantic Fishery Management Council... FURTHER INFORMATION CONTACT: Daniel T. Furlong, Executive Director, Mid-Atlantic Fishery Management...

  12. 78 FR 30779 - Snapper-Grouper Fishery of the South Atlantic; 2013 Recreational Accountability Measure and...

    Science.gov (United States)

    2013-05-23

    ... the South Atlantic; 2013 Recreational Accountability Measure and Closure for South Atlantic Snowy... (NOAA), Commerce. ACTION: Temporary rule; closure. SUMMARY: NMFS implements accountability measures (AMs...

  13. 77 FR 32914 - Snapper-Grouper Fishery of the South Atlantic; 2012 Recreational Accountability Measure and...

    Science.gov (United States)

    2012-06-04

    ... the South Atlantic; 2012 Recreational Accountability Measure and Closure for South Atlantic Golden... (NOAA), Commerce. ACTION: Temporary rule; closure. SUMMARY: NMFS implements accountability measures (AMs...

  14. 78 FR 32995 - Snapper-Grouper Fishery of the South Atlantic; 2013 Recreational Accountability Measure and...

    Science.gov (United States)

    2013-06-03

    ... the South Atlantic; 2013 Recreational Accountability Measure and Closure for South Atlantic Golden... (NOAA), Commerce. ACTION: Temporary rule; closure. SUMMARY: NMFS implements accountability measures (AMs...

  15. 76 FR 74724 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Science.gov (United States)

    2011-12-01

    ... United States; Atlantic Mackerel, Squid, and Butterfish Fisheries; Amendment 11 AGENCY: National Marine... implementing Amendment 11 to the Atlantic Mackerel, Squid, and Butterfish (MSB) Fishery Management Plan (FMP...

  16. 76 FR 39313 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Science.gov (United States)

    2011-07-06

    ... Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries; Closure of the Directed... under the Atlantic Mackerel, Squid, and Butterfish Fishery Management Plan (FMP). The procedures for...

  17. The Role of the Subtropical North Atlantic Water Cycle in the 2015 Extreme Precipitation Events in the US

    Science.gov (United States)

    Li, L.; Schmitt, R. W.; Ummenhofer, C.

    2016-12-01

    The role of the oceanic water cycle on the record-breaking 2015 warm-season precipitation in the US is analyzed. The extreme precipitation started in the Southern US in the spring and propagated northward to the Midwest and the Great Lakes in the summer of 2015. This seasonal evolution of precipitation anomalies represents a typical mode of variability of US warm-season precipitation. Analysis of the atmospheric moisture flux suggests that such a rainfall mode is associated with moisture export from the subtropical North Atlantic. In the spring, excessive precipitation in the Southern US is attributable to increased moisture flux from the northwestern portion of the subtropical North Atlantic. The North Atlantic moisture flux interacts with local soil moisture which enables the US Midwest to draw more moisture from the Gulf of Mexico in the summer. Further analysis shows that the relationship between the rainfall mode and the North Atlantic water cycle has become more significant in recent decades, indicating an increased likelihood of extremes like the 2015 case. Indeed, two record-high warm-season precipitation events, the 1993 and 2008 cases, both occurred in the more recent decades of the 66 year analysis period. The export of water from the North Atlantic leaves a marked surface salinity signature. The salinity signature appeared in the spring preceding all three extreme precipitation events analyzed in this study, i.e. a saltier-than-normal subtropical North Atlantic in spring followed by extreme Midwest precipitation in summer. Compared to the various sea surface temperature anomaly patterns among the 1993, 2008, and 2015 cases, the spatial distribution of salinity anomalies is much more consistent during these extreme flood years. Thus, our study suggests that preseason salinity patterns can be used for improved seasonal prediction of extreme precipitation in the Midwest.

  18. Interannual to multidecadal Euro-Atlantic blocking variability during winter and its relationship with extreme low temperatures in Europe

    Science.gov (United States)

    Rimbu, Norel; Lohmann, Gerrit; Ionita, Monica

    2014-12-01

    The dominant modes of blocking frequency variability in the Atlantic-European region are evaluated for the 1871-2010 period. An Empirical Orthogonal Function (EOF) analysis of a two-dimensional blocking indicator field reveals three dominant EOFs, describing about 35% of interannual to multidecadal blocking variability. The first EOF captures an out-of-phase blocking frequency anomaly over Greenland and Western Europe regions. The corresponding principal component time series is strongly correlated with the North Atlantic Oscillation index but shows also significant correlations with indices of the East Atlantic, Scandinavian, and East Atlantic-Western Russia patterns. The second EOF shows a dominant center over the North Sea region as well as a less pronounced center with anomalies of the same sign over southeastern Greenland. The multidecadal variations of this mode of blocking variability are related with a basin wide North Atlantic sea surface temperature anomaly which projects partly on the Atlantic Multidecadal Oscillation (AMO). The third mode is an east-west dipole of blocking frequency anomalies from Scandinavian and southern Greenland regions and shows enhanced variability at 20 year time scales. The coherent variations of the time coefficients of this pattern with open solar flux suggest a possible solar influence on blocking variability at these time scales. Furthermore, the dominant patterns of blocking variability are related with distinct anomaly patterns in the occurrence of extreme low temperature events over Europe at interannual to multidecadal time scales. AMO as well as the solar signals was detected also in the corresponding extreme low temperature blocking patterns. We argue that multivariate analysis of blocking indicators gives additional information about blocking and related extreme climate phenomena variability and predictability comparative with classical sectorial approach.

  19. Probabilistic tsunami hazard in the North East Atlantic due to seismic sources, implications for NEAMTWS

    Science.gov (United States)

    Omira, R.; Baptista, M.; Matias, L. M.; Miranda, J. M.; Carrilho, F.

    2013-12-01

    Recently, several studies on tsunami hazard assessment for the North East Atlantic coasts have been published. These studies use deterministic approach based upon the most credible earthquake scenario and/or the worst case scenario to derive tsunami coastal hazard in terms of wave elevation and inundation maps. In this work, we present the first thorough study on probabilistic tsunami hazard assessment due to earthquake sources for the North East Atlantic area. We consider three main seismogenic areas: the Gulf of Cadiz, the Gloria Fault and the Caribbean arc. For each seismogenic zone we derive the annual recurrence rate for each magnitude range, starting from Mw7.5 to Mw9.0, using the Bayesian method that incorporates seismic information from historical catalog and instrumental periods. A numerical code, solving the linear shallow water equations is employed to simulate the tsunami propagation and compute near shore wave heights along the entire NE Atlantic coast and at the forecast points of the NEAMTWS. To establish, for multiple sources, the joint probability that wave height exceeds a particular value for a given time period, we consider that the sources are independent (like in the Poison distribution). This process allows calculating the time-independent probability that wave height, simulated by numerical code, will be exceeded due to the occurrence of a tsunami source with a known average rate, derived from sources' recurrence assessment, during a period of time. The results are presented in terms of the probability of exceedance of a given tsunami amplitude for 100, 500 and 1000 years, and hazard curves for selected forecast points of the NEAMTWS countries. The level of hazard varies along the coast being maximum along the northern segment of the Morocco Atlantic coast, the southern Portuguese coast and the Spanish coast of the Gulf of Cadiz. The results show that the probability of a tsunami wave exceeding 1 m in the next 500 years reaches 100% in some

  20. CaMKIIdelta Subtypes: Localization and Function

    Directory of Open Access Journals (Sweden)

    Charles Burdis Burns Gray

    2014-02-01

    Full Text Available In this review we will discuss the localization and function of the known subtypes of calcium/calmodulin dependent protein kinase IIδ (CaMKIIδ and their role in cardiac physiology and pathophysiology. The CaMKII holoenzyme is comprised of multiple subunits that are encoded by four different genes called CaMKIIα, β, γ, and δ. While these four genes have a high degree of sequence homology, they are expressed in different tissues. CaMKIIα and β are expressed in neuronal tissue while γ and δ are present throughout the body, including in the heart. Both CaMKIIγ and δ are alternatively spliced in the heart to generate multiple subtypes. CaMKIIδ is the predominant cardiac isoform and is alternatively spliced in the heart to generate the CaMKIIδB subtype or the slightly less abundant δC subtype. The CaMKIIδB mRNA sequence contains a 33bp insert not present in δC that codes for an 11-amino acid nuclear localization sequence (NLS. This review will focus on the localization and function of the CaMKIIδ subtypes δB and δC and the role of these subtypes in arrhythmias, contractile dysfunction, gene transcription, and the regulation of Ca2+ handling.

  1. Ca2+ homeostasis regulates Xenopus oocyte maturation.

    Science.gov (United States)

    Sun, Lu; Hodeify, Rawad; Haun, Shirley; Charlesworth, Amanda; MacNicol, Angus M; Ponnappan, Subramaniam; Ponnappan, Usha; Prigent, Claude; Machaca, Khaled

    2008-04-01

    In contrast to the well-defined role of Ca2+ signals during mitosis, the contribution of Ca2+ signaling to meiosis progression is controversial, despite several decades of investigating the role of Ca2+ and its effectors in vertebrate oocyte maturation. We have previously shown that during Xenopus oocyte maturation, Ca2+ signals are dispensable for entry into meiosis and for germinal vesicle breakdown. However, normal Ca2+ homeostasis is essential for completion of meiosis I and extrusion of the first polar body. In this study, we test the contribution of several downstream effectors in mediating the Ca2+ effects during oocyte maturation. We show that calmodulin and calcium-calmodulin-dependent protein kinase II (CAMK2) are not critical downstream Ca2+ effectors during meiotic maturation. In contrast, accumulation of Aurora kinase A (AURKA) protein is disrupted in cells deprived of Ca2+ signals. Since AURKA is required for bipolar spindle formation, failure to accumulate AURKA may contribute to the defective spindle phenotype following Ca2+ deprivation. These findings argue that Ca2+ homeostasis is important in establishing the oocyte's competence to undergo maturation in preparation for fertilization and embryonic development.

  2. Dopamine elevates and lowers astroglial Ca2+ through distinct pathways depending on local synaptic circuitry.

    Science.gov (United States)

    Jennings, Alistair; Tyurikova, Olga; Bard, Lucie; Zheng, Kaiyu; Semyanov, Alexey; Henneberger, Christian; Rusakov, Dmitri A

    2017-03-01

    Whilst astrocytes in culture invariably respond to dopamine with cytosolic Ca2+ rises, the dopamine sensitivity of astroglia in situ and its physiological roles remain unknown. To minimize effects of experimental manipulations on astroglial physiology, here we monitored Ca2+ in cells connected via gap junctions to astrocytes loaded whole-cell with cytosolic indicators in area CA1 of acute hippocampal slices. Aiming at high sensitivity of [Ca2+ ] measurements, we also employed life-time imaging of the Ca2+ indicator Oregon Green BAPTA-1. We found that dopamine triggered a dose-dependent, bidirectional Ca2+ response in stratum radiatum astroglia, a jagged elevation accompanied and followed by below-baseline decreases. The elevation depended on D1/D2 receptors and engaged intracellular Ca2+ storage and removal whereas the dopamine-induced [Ca2+ ] decrease involved D2 receptors only and was sensitive to Ca2+ channel blockade. In contrast, the stratum lacunosum moleculare astroglia generated higher-threshold dopamine-induced Ca2+ responses which did not depend on dopamine receptors and were uncoupled from the prominent inhibitory action of dopamine on local perforant path synapses. Our findings thus suggest that a single neurotransmitter-dopamine-could either elevate or decrease astrocyte [Ca2+ ] depending on the receptors involved, that such actions are specific to the regional neural circuitry and that they may be causally uncoupled from dopamine actions on local synapses. The results also indicate that [Ca2+ ] elevations commonly detected in astroglia can represent the variety of distinct mechanisms acting on the microscopic scale. GLIA 2017;65:447-459. © 2016 The Authors Glia Published by Wiley Periodicals, Inc.

  3. Land use changes after the period commodities rising price in the Rio Grande do Sul State, Brazil

    Directory of Open Access Journals (Sweden)

    Vicente Celestino Pires Silveira

    Full Text Available ABSTRACT: At the end of the 20th and early 21st century, agricultural systems incorporated definitively a new mission: to generate goods for a world population that continues to grow and whose way of life demand food with low environmental impact. Soybean is the main raw material for the production of biodiesel in Brazil, accountably responsible for 82.4% of the total produced between 2006 and 2013. The Brazilian state of Rio Grande do Sul (RS, which is formed by the Pampa and the Atlantic forest biomes, was responsible for 35.7% of the country's biodiesel production in the referred period. The aim of this paper was to verify the impact of the increased area of soybean cultivation in land use in Rio Grande do Sul State, in the period between 1990 and 2015, considering separately its two biomes (Pampa and Atlantic Forest original areas, using both census dataset and satellite images. We used the period from 1990 to 2000 as before commodity rising price (BCRP and the period from 2000 to 2013 as commodity rising price (CRP. The 505,162 ha from Atlantic Forest biome and 1,192,115ha from Pampa biome were added to soybean production in the CRP period. In the Atlantic Forest, this enlargement occurred in the border of the main production area, while in Pampa biome conversion of natural grassland to crop land was the main reason for the large increment in the cultivated area.

  4. Hurricane intensification along United States coast suppressed during active hurricane periods

    Science.gov (United States)

    Kossin, James P.

    2017-01-01

    The North Atlantic ocean/atmosphere environment exhibits pronounced interdecadal variability that is known to strongly modulate Atlantic hurricane activity. Variability in sea surface temperature (SST) is correlated with hurricane variability through its relationship with the genesis and thermodynamic potential intensity of hurricanes. Another key factor that governs the genesis and intensity of hurricanes is ambient environmental vertical wind shear (VWS). Warmer SSTs generally correlate with more frequent genesis and greater potential intensity, while VWS inhibits genesis and prevents any hurricanes that do form from reaching their potential intensity. When averaged over the main hurricane-development region in the Atlantic, SST and VWS co-vary inversely, so that the two factors act in concert to either enhance or inhibit basin-wide hurricane activity. Here I show, however, that conditions conducive to greater basin-wide Atlantic hurricane activity occur together with conditions for more probable weakening of hurricanes near the United States coast. Thus, the VWS and SST form a protective barrier along the United States coast during periods of heightened basin-wide hurricane activity. Conversely, during the most-recent period of basin-wide quiescence, hurricanes (and particularly major hurricanes) near the United States coast, although substantially less frequent, exhibited much greater variability in their rate of intensification, and were much more likely to intensify rapidly. Such heightened variability poses greater challenges to operational forecasting and, consequently, greater coastal risk during hurricane events.

  5. Increased CaVβ1a Expression with Aging Contributes to Skeletal Muscle Weakness

    Science.gov (United States)

    Taylor, Jackson R.; Zheng, Zhenlin; Wang, Zhong-Min; Payne, Anthony M.; Messi, María L.; Delbono, Osvaldo

    2009-01-01

    Summary Ca2+ release from the sarcoplasmic reticulum (SR) into the cytosol is a crucial part of excitation-contraction (E-C) coupling. E-C uncoupling, a deficit in Ca2+ release from the SR, is thought to be responsible for at least some of the loss in specific force observed in aging skeletal muscle. E-C uncoupling may be caused by alterations in expression of the voltage-dependent calcium channel α1s (CaV1.1) and β1a (CaVβ1a) subunits, both of which are necessary for E-C coupling to occur. While previous studies have found CaV1.1 expression declines in old rodents, CaVβ1a expression has not been previously examined in aging models. Western blot analysis shows a substantial increase of CaVβ1a expression over the full lifespan of FVB mice. To examine the specific effects of CaVβ1a overexpression, a CaVβ1a -YFP plasmid was electroporated in vivo into young animals. The resulting increase in expression of CaVβ1a corresponded to decline of CaV1.1 over the same time period. YFP fluorescence, used as a measure of CaVβ1a -YFP expression in individual fibers, also showed an inverse relationship with charge movement, measured using the whole-cell patch-clamp technique. Specific force was significantly reduced in young CaVβ1a - YFP electroporated muscle fibers compared to sham-electroporated, age-matched controls. siRNA interference of CaVβ1a in young muscles reduced charge movement, while charge movement in old was restored to young control levels. These studies imply CaVβ1a serves as both a positive and negative regulator CaV1.1 expression, and that endogenous overexpression of CaVβ1a during old age may play a role in the loss of specific force. PMID:19663902

  6. Increased CaVbeta1A expression with aging contributes to skeletal muscle weakness.

    Science.gov (United States)

    Taylor, Jackson R; Zheng, Zhenlin; Wang, Zhong-Min; Payne, Anthony M; Messi, María L; Delbono, Osvaldo

    2009-09-01

    Ca2+ release from the sarcoplasmic reticulum (SR) into the cytosol is a crucial part of excitation-contraction (E-C) coupling. Excitation-contraction uncoupling, a deficit in Ca2+ release from the SR, is thought to be responsible for at least some of the loss in specific force observed in aging skeletal muscle. Excitation-contraction uncoupling may be caused by alterations in expression of the voltage-dependent calcium channel alpha1s (CaV1.1) and beta1a (CaVbeta1a) subunits, both of which are necessary for E-C coupling to occur. While previous studies have found CaV1.1 expression declines in old rodents, CaVbeta1a expression has not been previously examined in aging models. Western blot analysis shows a substantial increase of CaVbeta1a expression over the full lifespan of Friend Virus B (FVB) mice. To examine the specific effects of CaVbeta1a overexpression, a CaVbeta1a-YFP plasmid was electroporated in vivo into young animals. The resulting increase in expression of CaVbeta1a corresponded to decline of CaV1.1 over the same time period. YFP fluorescence, used as a measure of CaVbeta1a-YFP expression in individual fibers, also showed an inverse relationship with charge movement, measured using the whole-cell patch-clamp technique. Specific force was significantly reduced in young CaVbeta1a-YFP electroporated muscle fibers compared with sham-electroporated, age-matched controls. siRNA interference of CaVbeta1a in young muscles reduced charge movement, while charge movement in old was restored to young control levels. These studies imply CaVbeta1a serves as both a positive and negative regulator CaV1.1 expression, and that endogenous overexpression of CaVbeta1a during old age may play a role in the loss of specific force.

  7. Impact of the North Atlantic dipole on climate changes over Eurasia

    Science.gov (United States)

    Serykh, Ilya

    2017-04-01

    Hydrophysical and meteorological characteristics of negative (1948-1976, 1999-2015) and positive (1977-1998) phases of the Pacific Decadal Oscillation (PDO) / Interdecadal Pacific Oscillation (IPO) in the North Atlantic and Eurasia are constructed and investigated. Specifically, the near-surface temperature, sea-level atmospheric pressure, wind speed, heat content of the upper 700 m ocean layer, water temperature and salinity at various depths, the latent and sensible heat fluxes from the ocean to the atmosphere are analyzed. The fields obtained from different sources (20thC_ReanV2c, ERA-20C, JRA-55, NCEP/NCAR, HadCRUT4, HadSLP2, NODC, Ishii, SODA, OAFlux, HadSST3, COBE2, ERSSTv4) are in good agreement and complement each other. This gives important information about the hydrometeorological conditions in the region under study. Analysis of these data has shown that in the upper 1000 m North Atlantic layer there is a thermal dipole which can be interpreted as an oceanic analog of the atmospheric North Atlantic Oscillation (NAO). An index of the North Atlantic Dipole (NAD) as the difference between the mean heat contents in the upper 700 m oceanic layer between the regions (50°-70° N; 60°-10° W) and (20°-40° N; 80°-30° W) is proposed. A possible physical mechanism of the internal oscillations with a quasi-60-year period in the North Atlantics-Eurasia system of ocean-atmosphere interactions is discussed. Dipole spatial structure from observations datasets and re-analyses were compared with the results of the Historical Experiment from the climate models of the CMIP5 project. It is found that several climate models reproduce dipole spatial structure of the near-surface temperature and sea level pressure anomalies similarly to these fields in the re-analyses considered. However, the phase diagrams of the gradient of near-surface temperature and sea level pressure between the Azores High and Island Low from climate models do not separate on subsets as the

  8. New insights into cycling of 231Pa and 230Th in the Atlantic Ocean

    Science.gov (United States)

    Rempfer, Johannes; Stocker, Thomas F.; Joos, Fortunat; Lippold, Jörg; Jaccard, Samuel L.

    2017-06-01

    We use the Bern3D model of intermediate complexity to examine the marine cycle of isotopes 231Pa and 230Th and the relationship between the particle-bound ratio Pap /Thp and changes in the formation of the North Atlantic Deep Water (NADW). Model parameters describing reversible scavenging of isotopes by organic particles, opal, calcite and resuspended sediments were systematically varied and alternative sink parametrisations explored. It proves difficult to simultaneously achieve a good agreement with observations of dissolved and particle-associated concentrations of 231Pa and 230Th (Pad, Thd, Pap, Thp) as well as the particle-bound ratio Pap /Thp within the classical concept of reversible scavenging alone. Agreement between simulated and observed Pad, Thd and estimates of mean ocean residence times is improved by taking into account simplified representations of additional sinks at the sea floor (bottom scavenging) and at continental boundaries (boundary scavenging). We also find improved agreement between model and data by increasing lateral advection, in particular for Pad. These results point to the importance of sink processes that act in addition to reversible scavenging to shape the steady state distribution of 231Pa and, to a lesser degree, of 230Th. In transient experiments in which the strength of the Atlantic meridional overturning circulation (AMOC) is periodically turned on and off, we find a strong statistical relationship between variations in AMOC strength and Pap /Thp at great depths in the Northwest Atlantic region. These conclusions are robust across the range of sink parametrisations, that are consistent with estimates in the mean ocean residence time of 231Pa and 230Th. Our results indicate that the relationship between Pap /Thp and AMOC-strength may not be fundamentally affected by uncertainties in sink processes, at least on the large spatial and temporal scale considered here, and support the idea that changes in Pap /Thp in sediments of

  9. Microearthquakes at the active Trans-Atlantic Geotraverse (TAG) hydrothermal mound, Mid-Atlantic Ridge, 26°08'N

    Science.gov (United States)

    Pontbriand, C.; Reves-Sohn, R. A.

    2010-12-01

    A small 200 m aperture network of five ocean bottom seismometers around the periphery the active TAG hydrothermal mound on the Mid-Atlantic Ridge (26°08’N) detected microearthquake events that may be associated with the subsurface hydraulics of the massive hydrothermal deposit. Seismic data were sampled at 100 Hz for a period of eight months spanning June, 2003 to February, 2004, during which time 24,191 locatable events were detected. Microearthquake hypocenters are concentrated within a 300 m radius of the sulfide mound in the top 250 m of crust, and exhibit a conical shape with the deepest events beneath the mound center. Event rates are steady at 180 events per day at the beginning of the study period and decline slightly to 116 events per day after whale calls elevate background noise levels about 2/3 of the way through the deployment. The mean local magnitude of events is -1.2 with a range of -2.9≦ML≦0.3. We suggest that events may be largely due to hydraulic fracturing of clogged flow conduits in the mineral deposit, which provides the possibility of using the microearthquake data to constrain subsurface flow parameters and the permeability structure of the active TAG deposit. Figure: A bathymetric map of the TAG area depicts a small aperture network of 5 ocean bottom seismometers (white triangles) around the periphery of the active TAG hydrothermal mound. High resolution bathymetry is from Roman and Singh, 2005.

  10. Distribution and abundance of fin whales (Balaenoptera physalus in the Northeast and Central Atlantic as inferred from the North Atlantic Sightings Surveys 1987-2001

    Directory of Open Access Journals (Sweden)

    Gísli A Víkingsson

    2013-10-01

    Full Text Available North Atlantic Sightings Surveys (NASS is a series of large scale international cetacean line transect surveys, conducted in 1987, 1989, 1995 and 2001, that covered a large part of the central and eastern North Atlantic. Target species were fin (Balaenoptera physalus, common minke (B. acutorostrata, pilot (Globicephala melas and sei (B. borealis whales. Here we present new estimates of abundance for fin whales from the 2 most recent surveys and analysis of trends throughout the survey period. Fin whales were found in highest densities in the Irminger Sea between Iceland and Greenland. Abundance of fin whales in the survey area of the Icelandic and Faroese vessels (Central North Atlantic was estimated as 19,672 (95% C.I. 12,083-28,986 animals in 1995 and 24,887 (95% C.I. 18,186-30,214 in 2001. The estimates are negatively biased because of whales diving during the passage of vessels, and whales being missed by observers, but these and other potential biases are likely small for this species. The abundance of fin whales increased significantly over the survey period. For all areas combined the estimated annual growth rate was 4%. An estimated annual increase of 10% in the area between Iceland and Greenland was responsible for most of this overall increase in numbers of fin whales in the area. Although high, the estimated rates of increase are not out of bounds of biological plausibility and can thus be viewed as recovery of a depleted population. However, the apparent pattern of population growth and the whaling history in the area indicate that fin whales made a significant recovery during the first half of the 20th century and that the recent observed high growth rates cannot be explained solely by recovery after overexploitation.

  11. Advection of Atlantic Water to the Western and Northern Svalbard Shelves Through the Last 17.5 ka cal yr BP

    Science.gov (United States)

    Slubowska, M. A.; Rasmussen, T. L.; Koc, N.; Kristensen, D. K.; Nilsen, F.; Solheim, A.

    2005-12-01

    We have studied the distribution of benthic foraminifera species together with planktonic and benthic foraminifera abundances, stable oxygen isotopes and lithology in two cores: JM02-440 from the western (77° 22' N, 12° 48' E, 240 m water depth) and NP94-51 from the northern (80° 21' N and 16 ° 17' E, 400 m water depth) shelf of Svalbard. The purpose of the study was to reconstruct the changes in flow and character of the relatively warm Atlantic Water through the last 17.5 ka cal yr BP. The results from these two sites were compared with previously published records from the eastern Nordic Seas in order to follow the history of the advection of Atlantic Water as it moved northwards along the Norwegian coast and into the Arctic Ocean. Our results indicate that synchronous oceanographic changes occurred at the western and northern Svalbard shelves. The benthic foraminifera and oxygen isotope records indicate almost continuous presence of the Atlantic Water at the shelf areas since the deglaciation. The Bolling-Allerod period stands out as the warmest period in our records with the highest bottom waters temperatures indicating strong inflow of Atlantic Water. However, the warm Atlantic Water was isolated below cold and probably sea ice covered surface waters in contrast to the surface waters along the Norwegian coast, which experienced enhanced temperatures. During the Younger Dryas a freshening of the bottom waters occurred and the Polar Front was located in a proximal position to both sites. The strong inflow of saline, but chilled Atlantic Water happened during the Early Holocene. A distinct cooling and freshening of the bottom water masses occurred during the Mid- and Late Holocene, and was accompanied by glacier re-advances leading to the present-day conditions. During the last millennium, the inflow of Atlantic Water appears to increase, but the conditions turned unstable. The development of the paleoceanographic conditions at the western and northern

  12. The postanesthetic period. Complications.

    Science.gov (United States)

    Malamed, S F

    1987-01-01

    Postanesthetic complications can occur even in the best of circumstances. Proper preparation of the staff, aggressive monitoring of the recovering patient, and early recognition and management of the complications are essential if the outcome is to be successful. In reviewing postanesthetic complications, two factors are present in the overwhelming majority of situations--hypoxia and hypercarbia--often the direct result of inadequate monitoring during the postanesthetic period. The anesthetic procedure is not over once the anesthetic agents are discontinued. The skillful anesthetist is aware of the possibilities of postoperative complications and prevents problems by employing enhanced monitoring techniques during the recovery phase.

  13. Periods of Hecke characters

    CERN Document Server

    Schappacher, Norbert

    1988-01-01

    The starting point of this Lecture Notes volume is Deligne's theorem about absolute Hodge cycles on abelian varieties. Its applications to the theory of motives with complex multiplication are systematically reviewed. In particular, algebraic relations between values of the gamma function, the so-called formula of Chowla and Selberg and its generalization and Shimura's monomial relations among periods of CM abelian varieties are all presented in a unified way, namely as the analytic reflections of arithmetic identities beetween Hecke characters, with gamma values corresponding to Jacobi sums. The last chapter contains a special case in which Deligne's theorem does not apply.

  14. Evidence for Large Hydrologic and Ecologic Variability During the Late Wisconsin in the Coastal Southwest United States (Lake Elsinore, CA)

    Science.gov (United States)

    Kirby, M.; Heusser, L. E.; Scholz, C. A.; Anderson, M.; Rhodes, E. J.; Hiner, C.; Palermo, J. A.; Silveira, E.

    2016-12-01

    Future climate change is expected to alter the planet's water cycle, thus stressing water resources and ecologic stability. This impact is predicted to be especially significant in arid environments. Unfortunately, continuous, sub-centennially resolved paleo-terrestrial records are rare from arid environments such as the coastal southwest US (cswUS). Lake Elsinore, a pull-apart basin located 90 km SE of Los Angeles CA, is the largest natural lake in the cswUS. Gravity studies indicate nearly 1000 m of sediments occupy the basin. A recent seismic reflection survey imaged the upper 60-80 m of sediment, revealing continuous sediment accumulation. Here, we present a decadal-to-multi-decadal lacustrine sediment core record used to assess the relationship between vegetation (i.e., pollen) and run-off variability (i.e., grain size) during the late Wisconsin (10-32 kyrs BP). In general, the late Wisconsin is characterized by run-off greater than during the Holocene, indicating more frequent winter storms and/or higher intensity precipitation. A notable dry period, however, exists between 25.5-27.5 kyrs BP (Heusser et al., 2015), where lake level regressed but did not desiccate. Modern lake-level - grain size relationships are used to assess paleo-lake levels during this glacial mega-drought. Peak run-off occurs between 14.7 and 19.8 kyrs BP, generally post-dating the global LGM. A two-step decrease in run-off characterize the B-A to YD to Holocene (Kirby et al., 2013). Vegetation shows a fairly strong coupling to the run-off indicator, signifying rapid ecologic responses to changes in regional hydroclimates. This run-off - vegetation coupling is especially relevant to understanding future vegetative responses in the CA Floristic Province Biodiversity Hotspot. Finally, results are compared to potential forcings such as winter-summer insolation, Pacific SSTs, and Atlantic Meridional Overturning Circulation as well as regional paleo-records.

  15. Ca2+ cycling in heart cells from ground squirrels: adaptive strategies for intracellular Ca2+ homeostasis.

    Directory of Open Access Journals (Sweden)

    Xiao-Chen Li

    Full Text Available Heart tissues from hibernating mammals, such as ground squirrels, are able to endure hypothermia, hypoxia and other extreme insulting factors that are fatal for human and nonhibernating mammals. This study was designed to understand adaptive mechanisms involved in intracellular Ca(2+ homeostasis in cardiomyocytes from the mammalian hibernator, ground squirrel, compared to rat. Electrophysiological and confocal imaging experiments showed that the voltage-dependence of L-type Ca(2+ current (I(Ca was shifted to higher potentials in ventricular myocytes from ground squirrels vs. rats. The elevated threshold of I(Ca did not compromise the Ca(2+-induced Ca(2+ release, because a higher depolarization rate and a longer duration of action potential compensated the voltage shift of I(Ca. Both the caffeine-sensitive and caffeine-resistant components of cytosolic Ca(2+ removal were more rapid in ground squirrels. Ca(2+ sparks in ground squirrels exhibited larger amplitude/size and much lower frequency than in rats. Due to the high I(Ca threshold, low SR Ca(2+ leak and rapid cytosolic Ca(2+ clearance, heart cells from ground squirrels exhibited better capability in maintaining intracellular Ca(2+ homeostasis than those from rats and other nonhibernating mammals. These findings not only reveal adaptive mechanisms of hibernation, but also provide novel strategies against Ca(2+ overload-related heart diseases.

  16. A 450 000 kyr Surface Hydrography History From the Subantarctic Atlantic Ocean (ODP Site 1089)

    Science.gov (United States)

    Cortese, G.; Abelmann, A.; Gersonde, R.

    2002-12-01

    We established a palaeo sea surface temperature (SST) record, by using a radiolarian-based transfer function, for the northern subantarctic Atlantic Ocean (ODP Site 1089, 400 56' S; 90 54 E), in order to reconstruct its surface hydrography and interocean heat exchange history during the last five climate cycles (ca. 450 ka). The produced record has a centennial scale time resolution, which makes it unique (in length and resolution) for the subantarctic zone. At this location, close to the subtropical front, ocean/atmosphere interactions, interoceanic exchange processes, and mesoscale eddy mixing play an important role in shaping the characteristics of sea water eventually advected to the North Atlantic. The centennial resolution allows to recognize millennial scale climatic events, similar to the Dansgaard-Oeschger cycles (originally described from Greenland ice cores), both during Marine Isotopic Stage (MIS) 3 and 6. Similar to observations from Termination I (Antarctic Cold Reversal), rapid cooling rebounds were encountered at Terminations II to V, and are not therefore limited either to the circum-Atlantic area or to last Termination. A comparison of SST and ice volume proxies suggests a lead of a few kyrs between SST and the minimum extent of global ice volume, indicating that temperatures rose substantially at subantarctic latitudes before any considerable northern hemisphere continental ice volume change was recorded. The climatic history of ODP Site 1089 displays good correlation to other records (e.g. Vostok) with the exception of MIS 10, where a warm SST anomaly was recognized. This anomaly is also present in oceanic records along the thermohaline circulation belt path, but absent in both Polar Zone and Vostok climatic records. The implications of our record for interhemispheric climate connecting mechanisms and the role played by the Southern Ocean in steering global climatic change will be discussed.

  17. 78 FR 44095 - Atlantic Highly Migratory Species; Meeting of the Atlantic Highly Migratory Species Advisory Panel

    Science.gov (United States)

    2013-07-23

    ...; shark management measures regarding rebuilding scalloped hammerhead and blacknose sharks (Amendment 5a), rebuilding dusky sharks (Amendment 5b), and shark catch shares (Amendment 6); and swordfish management... Atlantic tunas, swordfish, billfish, and sharks. The AP has previously consulted with NMFS on: Amendment 1...

  18. 77 FR 4282 - Atlantic Highly Migratory Species; Meeting of the Atlantic Highly Migratory Species Advisory Panel

    Science.gov (United States)

    2012-01-27

    ... tuna management; revitalizing the swordfish fishery; shark management measures such as rebuilding scalloped hammerhead, dusky, and blacknose sharks and catch shares; and items contained in the Advanced... FMP amendments for Atlantic tunas, swordfish, billfish, and sharks. The AP has previously consulted...

  19. 76 FR 62042 - Fisheries of the South Atlantic; South Atlantic Fishery Management Council; Public Meeting

    Science.gov (United States)

    2011-10-06

    ... and Education Advisory Panel (AP) and a Social Media Workshop in conjunction with the South Carolina... Social Media Workshop will be conducted from 1:30 p.m. until 5 p.m. on October 26, 2011 and from 8:30 a.m... Special Management Zones in the South Atlantic Exclusive Economic Zone, and strategic planning for...

  20. 75 FR 30732 - Atlantic Highly Migratory Species; 2010 Atlantic Bluefin Tuna Quota Specifications

    Science.gov (United States)

    2010-06-02

    ... Species (HMS) Management Division, Office of Sustainable Fisheries (F/SF1), NMFS, 55 Great Republic Drive... Atlantic bluefin tuna stock (ICCAT Recommendation 08-04), i.e., 50 percent of the U.S. quota, or 488.7 mt... landings is now available, and it indicates a total 2009 underharvest of 388.6 mt. Thus, in this final...

  1. 78 FR 12705 - Atlantic Highly Migratory Species; North and South Atlantic 2013 Commercial Swordfish Quotas

    Science.gov (United States)

    2013-02-25

    ... will be accepted in Microsoft Word, Excel, or Adobe PDF file formats only. NMFS will hold one public..., and do not include dead discards. We will adjust the quotas in the final rule based on updated data, including dead discard data, if available. Thus, while the 2013 proposed North Atlantic swordfish quota is...

  2. The North Atlantic Oscillation: variability and interactions with the North Atlantic ocean and Artic sea ice

    Energy Technology Data Exchange (ETDEWEB)

    Jung, T.

    2000-07-01

    The North Atlantic oscillation (NAO) represents the dominant mode of atmospheric variability in the North Atlantic region and describes the strengthening and weakening of the midlatitude westerlies. In this study, variability of the NAO during wintertime and its relationship to the North Atlantic ocean and Arctic sea ice is investigated. For this purpose, observational data are analyzed along with integrations of models for the Atlantic ocean, Arctic sea ice, and the coupled global climate system. From a statistical point of view, the observed NAO index shows unusually high variance on interdecadal time scales during the 20th century. Variability on other time scales is consistent with realizations of random processes (''white noise''). Recurrence of wintertime NAO anomalies from winter-to-winter with missing signals during the inbetween nonwinter seasons is primarily associated with interdecadal variability of the NAO. This recurrence indicates that low-frequency changes of the NAO during the 20th century were in part externally forced. (orig.)

  3. 78 FR 24148 - Atlantic Highly Migratory Species; Atlantic Shark Management Measures

    Science.gov (United States)

    2013-04-24

    ... Species; Atlantic Shark Management Measures AGENCY: National Marine Fisheries Service (NMFS), National... Plan (FMP) to address the results of recent shark stock assessments for several shark species, including dusky sharks. In that notice, based on the 2010/2011 Southeast Data, Assessment and Review (SEDAR...

  4. 77 FR 31562 - Atlantic Highly Migratory Species; Atlantic Shark Management Measures

    Science.gov (United States)

    2012-05-29

    ... Species; Atlantic Shark Management Measures AGENCY: National Marine Fisheries Service (NMFS), National... considering the inclusion of Gulf of Mexico blacktip sharks in an amendment to the 2006 Consolidated Highly..., sandbar, and blacknose sharks. A new stock assessment is ongoing for Gulf of Mexico blacktip sharks, and...

  5. 75 FR 50715 - Atlantic Highly Migratory Species; Atlantic Shark Management Measures; Amendment 3

    Science.gov (United States)

    2010-08-17

    ... Migratory Species; Atlantic Shark Management Measures; Amendment 3 AGENCY: National Marine Fisheries Service.... This change ensures that the process is preserved for adjusting annual shark quotas based on over- and..., among other things, pelagic shark quotas and annual quota adjustments. The instructions, however...

  6. Ca isotope fractionation on the moon

    Science.gov (United States)

    Russell, W. A.; Papanastassiou, D. A.; Tombrello, T. A.; Epstein, S.

    1977-01-01

    Ca has been measured in a lunar soil in order to establish the presence of isotopically mass-fractionated components. Ca was extracted by a series of water leaches after the soils were 'activated' by brief exposures to fluorine gas. The O2 obtained by this fluorination is found to have delta (O-18) of +21 per mil and to be, therefore, significantly mass-fractionated. Ca obtained in the leaches was analyzed using the double-spike technique. Very small Ca isotope fractionation is found in the leaches of this soil of up to 1 per mil per mass unit difference. The small Ca effects are in marked contrast to the measured delta (O-18) for the same sample and to large effects observed in many soils for oxygen, silicon, sulfur, and potassium. The data on Ca provide stringent constraints on models which attempt to explain the isotope mass-fractionation effects in lunar soils.

  7. Meddies in the Mercator North Atlantic and Mediterranean Sea eddy-resolving model

    Science.gov (United States)

    Drillet, Yann; Bourdallé-Badie, Romain; Siefridt, Laure; Le Provost, Christian

    2005-03-01

    The new generation of high-resolution ocean models offers a new way to investigate the characteristics and the evolution of the ocean mesoscale. An analysis of the simulated Mediterranean eddies, the so-called "meddies," is presented. The model used in this study is the Mercator North Atlantic [9°N, 70°N] and Mediterranean Sea Prototype (PAM), a high-resolution configuration (3.5-8 km horizontal grid) based on the OPA ocean general circulation model. The meddies are coherent structures of warm and salt Mediterranean Water (MW) advected in the northeast Atlantic. A 5 year experiment performed with PAM reproduced the main observed characteristics of the meddies: thermohaline properties (11.8°C, 36 psu), sizes (radius between 25 and 110 km), thickness (between 500 and 1000 m), westward advection velocities (1.4 cm.s-1), angular velocities (a period of 20 days), a good estimate of the number of meddies in the northeast Atlantic (˜22), and their realistic geographical distribution (80% south of 40°N). Moreover, and in agreement with a previous study based on an observation cruise, these modeled meddies represent half of the westward salinity transport of MW.

  8. The North Atlantic spring-bloom system - where the changing climate meets the winter dark

    Directory of Open Access Journals (Sweden)

    Svein eSundby

    2016-03-01

    Full Text Available The North Atlantic with its spring-bloom ecosystem has its particular responses to climate change, many of them different from the other parts of the world’s oceans. The system is strongly influenced by anthropogenic climate change as well as to strong decadal to multidecadal natural climate variability. In particular, the northernmost part of the system and the Arctic is exposed to higher increase in temperature than any other ocean region. The most pronounced examples of poleward migration of marine species are found in the North Atlantic, and comprise the recent warming phase after the 1970s. The latitudinal asymmetric position of the Arctic Front and its nature of change result in a considerably larger migration distance and migration speed of species in the Northeast Atlantic part of the system. However, we here hypothesize that there is a limit to the future extent of poleward migration of species constrained by the latitudinal region adjacent the Polar Circle. We define this region the critical latitudes. This is because the seasonal light cycle at high latitudes sets particular demands on the life cycle of planktivore species. Presently, boreal planktivore species at high latitudes deposit lipids during the short spring bloom period and overwinter when phytoplankton production is insufficient for feeding. Unless invading temperate species from farther south are able to adapt by developing a similar life cycle future poleward migration of such species will be unlikely.

  9. Response of the North Atlantic surface and intermediate ocean structure to climate warming of MIS 11

    Science.gov (United States)

    Kandiano, Evgenia S.; van der Meer, Marcel T. J.; Schouten, Stefan; Fahl, Kirsten; Sinninghe Damsté, Jaap S.; Bauch, Henning A.

    2017-04-01

    Investigating past interglacial climates not only help to understand how the climate system operates in general, it also forms a vital basis for climate predictions. We reconstructed vertical stratification changes in temperature and salinity in the North Atlantic for a period some 400 ka ago (MIS11), an interglacial time analogue of a future climate. As inferred from a unique set of biogeochemical, geochemical, and faunal data, the internal upper ocean stratification across MIS 11 shows distinct depth-dependent dynamical changes related to vertical as well as lateral shifts in the upper Atlantic meridional circulation system. Importantly, transient cold events are recognized near the end of the long phase of postglacial warming at surface, subsurface, mid, and deeper water layers. These data demonstrate that MIS 11 coolings over the North Atlantic were initially triggered by freshwater input at the surface and expansion of cold polar waters into the Subpolar Gyre. The cooling signal was then transmitted downwards into mid-water depths. Since the cold events occurred after the main deglacial phase we suggest that their cause might be related to continuous melting of the Greenland ice sheet, a mechanism that might also be relevant for the present and upcoming climate.

  10. Climatological coupling of the thermohaline decadal changes in Central Water of the Eastern North Atlantic

    Directory of Open Access Journals (Sweden)

    F. F. Pérez

    2000-09-01

    Full Text Available Data collected at 42ºN, 10ºW in the intergyre region of the Northeast Atlantic show significant year to year variability in the T-S characteristics of the upper 800m of the water column. Taking salinity values on the sq = 27.1 kg m-3 isopycnal as representative of the Eastern North Atlantic Central Water mass it was found that the variability correlates well with the wind stress at 43ºN, 11ºW, with cumulative river discharge (which we take as an index of precipitation over the ocean and with the NAO (which is an index of the strength and position of storm tracks and the state of the evaporation-precipitation balance. The covariation illustrates the close coupling between water mass formation and climate in the North Atlantic, where climate changes affect the deep ventilation by which ENACW is formed and the evaporation-precipitation balance from which the T-S signature results. Hints of a 20 year cycle in the ocean correlate with a 20 year periodicity in the NAO. It remains to be established whether there is a feedback mechanism by which water mass anomalies affect the climate and the intensity and variation of the NAO pattern, and the extent to which upper ocean observations can be used as an indicator of future climate trends.

  11. Seasonal cycle of near-surface freshwater budget in the western tropical Atlantic

    Science.gov (United States)

    Romanova, V.; KöHl, A.; Stammer, D.

    2011-07-01

    We investigate differences of the ocean response in the Amazon domain to the seasonal variability of the river discharge that are either introduced via assimilating climatological temperature and salinity or by specifying seasonally varying river runoff. The role of the seasonal cycle of the Amazon freshwater discharge for the evolution of the barrier layer (BL) in the western tropical Atlantic and on the freshwater budget is estimated. During the experiments, three different runoff fields are being applied, including a time-mean runoff, a seasonally varying runoff, and one that results from the GECCO assimilation approach. The simulation forced with a seasonal Amazon discharge appears to be closer to the constrained solution and moves away from the run with a constant runoff, demonstrating that the seasonal variability of the Amazon is an essential contributor in the freshwater forcing of the western tropical Atlantic. The modeled time-mean BL thickness seems to be overestimated by the model relative to the data. On the seasonal timescale, the simulated spatial mean BL is found to vary between 13 and 30 m, with a maximum occurring in July, following the Amazon high discharge period in May. Analyzing the freshwater content balance, we find integrated near-surface freshwater import from the western tropical Atlantic interior of around 0.20 Sv in October-November at 38°W and cumulative freshwater export out of the domain with a maximum of around 0.4 Sv in June as an effect of the Amazon flood in May.

  12. A Detailed Assessment of the Wave Energy Resource at the Atlantic Marine Energy Test Site

    Directory of Open Access Journals (Sweden)

    Reduan Atan

    2016-11-01

    Full Text Available Wave characteristic assessments of wave energy test sites provide a greater understanding of prevailing wave conditions and are therefore extremely important to both wave energy test site operators and clients as they can inform wave energy converter design, optimisation, deployment, operation and maintenance. This research presents an assessment of the wave resource at the Atlantic Marine Energy Test Site (AMETS on the west coast of Ireland based on 12-years of modelled data from January 2004 to December 2015. The primary aim is to provide an assessment of annual and seasonal wave characteristics and resource variability at the two deployment berths which comprise the site. A nested model has been developed using Simulating WAves Nearshore (SWAN to replicate wave propagations from regional to local scale with a 0.05° resolution model covering the northeast Atlantic and a 0.0027° resolution model covering AMETS. The coarse and fine models have been extensively validated against available measured data within Irish waters. 12-year model outputs from the high resolution model were analysed to determine mean and maximum conditions and operational, high and extreme event conditions for significant wave height, energy period and power. Annual and seasonal analyses are presented. The 12-year annual mean P were 68 kW/m at Berth A (BA and 57 kW/m at Berth B (BB. The resource shows strong seasonal and annual variations and the winter mean power levels were found to be strongly correlated with the North Atlantic Oscillation (NAO.

  13. Hydro-environmental factors and phytoplankton of the Atlantic ...

    African Journals Online (AJOL)

    Hydro-environmental factors and phytoplankton of the Atlantic Ocean, off the Light House Beach, Lagos, Nigeria. ... hydro-environmental factors and phytoplankton components reflected a tropical unpolluted neritic and oceanic environment. Keywords: Physico-chemistry, micro-algae, sea, Lighthouse Beach, Atlantic Ocean ...

  14. 78 FR 11156 - South Atlantic Fishery Management Council; Public Meeting

    Science.gov (United States)

    2013-02-15

    ... (MREP) and Managing Our Nations' Fisheries 3 Conference. 2. Receive an update on the use of social media tools, including: The Atlantic Coast Communication Group Social Media Workshop; the status of the... South Atlantic/Gulf of Mexico Mackerel Amendment 19, pertaining to permits and tournament sale...

  15. 77 FR 50988 - South Atlantic Fishery Management Council; Public Meetings

    Science.gov (United States)

    2012-08-23

    ... of management history and current regulations for mutton snapper, greater amberjack, gray triggerfish... National Oceanic and Atmospheric Administration RIN 0648-XC177 South Atlantic Fishery Management Council... Administration (NOAA), Commerce. ACTION: Notice of public meetings of the South Atlantic Fishery Management...

  16. Farmed Atlantic salmon: potential invader in the Pacific Northwest?

    Science.gov (United States)

    Jonathan Thompson; Pete Bisson

    2008-01-01

    Commercial farming of Atlantic salmon in marine net-pens has become a booming industry. At present, approximately 130 salmon farms exist along the Pacific coast of North America. Most of these farms are in cold marine bays within British Columbia, where farmed salmon have become the province’s most valuable agricultural export. Each year, thousands of farmed Atlantic...

  17. Opal phytoliths in a north atlantic dust fall.

    Science.gov (United States)

    Folger, D W; Burckle, L H; Heezen, B C

    1967-03-10

    Minute bodies (less than 80 microns) of isotropic silica, originally precipitated by terrestrial plants, are found together with freshwater diatoms in falls of dust over the ocean. Eolian transport from Africa can explain the occurrence of similar plant remains in deep-sea sediments of the equatorial Atlantic as far west as the Mid-Atlantic Ridge.

  18. Cell Biology of Ca2+-Triggered Exocytosis

    OpenAIRE

    Pang, Zhiping P.; Südhof, Thomas C.

    2010-01-01

    Ca2+ triggers many forms of exocytosis in different types of eukaryotic cells, for example synaptic vesicle exocytosis in neurons, granule exocytosis in mast cells, and hormone exocytosis in endocrine cells. Work over the last two decades has shown that synaptotagmins function as the primary Ca2+-sensors for most of these forms of exocytosis, and that synaptotagmins act via Ca2+-dependent interactions with both the fusing phospholipid membranes and the membrane fusion machinery. However, some...

  19. Influence of soil characteristics on the diversity of bacteria in the Southern Brazilian Atlantic Forest.

    Science.gov (United States)

    Faoro, H; Alves, A C; Souza, E M; Rigo, L U; Cruz, L M; Al-Janabi, S M; Monteiro, R A; Baura, V A; Pedrosa, F O

    2010-07-01

    The Brazilian Atlantic Forest is one of the 25 biodiversity hot spots in the world. Although the diversity of its fauna and flora has been studied fairly well, little is known of its microbial communities. In this work, we analyzed the Atlantic Forest ecosystem to determine its bacterial biodiversity, using 16S rRNA gene sequencing, and correlated changes in deduced taxonomic profiles with the physicochemical characteristics of the soil. DNAs were purified from soil samples, and the 16S rRNA gene was amplified to construct libraries. Comparison of 754 independent 16S rRNA gene sequences from 10 soil samples collected along a transect in an altitude gradient showed the prevalence of Acidobacteria (63%), followed by Proteobacteria (25.2%), Gemmatimonadetes (1.6%), Actinobacteria (1.2%), Bacteroidetes (1%), Chloroflexi (0.66%), Nitrospira (0.4%), Planctomycetes (0.4%), Firmicutes (0.26%), and OP10 (0.13%). Forty-eight sequences (6.5%) represented unidentified bacteria. The Shannon diversity indices of the samples varied from 4.12 to 3.57, indicating that the soils have a high level of diversity. Statistical analysis showed that the bacterial diversity is influenced by factors such as altitude, Ca(2+)/Mg(2+) ratio, and Al(3+) and phosphorus content, which also affected the diversity within the same lineage. In the samples analyzed, pH had no significant impact on diversity.

  20. SR-targeted CaMKII inhibition improves SR Ca2+ handling, but accelerates cardiac remodeling in mice overexpressing CaMKIIδC

    Science.gov (United States)

    Huke, Sabine; DeSantiago, Jaime; Kaetzel, Marcia A.; Mishra, Shikha; Brown, Joan H.; Dedman, John R.; Bers, Donald M.

    2010-01-01

    Cardiac myocyte overexpression of CaMKIIδC leads to cardiac hypertrophy and heart failure (HF) possibly caused by altered myocyte Ca2+ handling. A central defect might be the marked CaMKII-induced increase in diastolic sarcoplasmic reticulum (SR) Ca2+ leak which decreases SR Ca2+ load and Ca2+ transient amplitude. We hypothesized that inhibition of CaMKII near the SR membrane would decrease the leak, improve Ca2+ handling and prevent the development of contractile dysfunction and HF. To test this hypothesis we crossbred CaMKIIδC overexpressing mice (CaMK) with mice expressing the CaMKII-inhibitor AIP targeted to the SR via a modified phospholamban (PLB)-transmembrane-domain (SR-AIP). There was a selective decrease in the amount of activated CaMKII in the microsomal (SR/membrane) fraction prepared from these double-transgenic mice (CaMK/SR-AIP) mice. In ventricular cardiomyocytes from CaMK/SR-AIP mice, SR Ca2+ leak, assessed both as diastolic Ca2+ shift into SR upon tetracaine in intact myocytes or integrated Ca2+ spark release in permeabilized myocytes, was significantly reduced. The reduced leak was accompanied by enhanced SR Ca2+ load and twitch amplitude in double-transgenic mice (vs. CaMK), without changes in SERCA expression or NCX function. However, despite the improved myocyte Ca2+ handling, cardiac hypertrophy and remodeling was accelerated in CaMK/SR-AIP and cardiac function worsened. We conclude that while inhibition of SR localized CaMKII in CaMK mice improves Ca2+ handling, it does not necessarily rescue the HF phenotype. This implies that a non-SR CaMKIIδC exerts SR-independent effects that contribute to hypertrophy and HF, and this CaMKII pathway may be exacerbated by the global enhancement of Ca transients. PMID:20971119

  1. Inter-population ovarian fluid variation differentially modulates sperm motility in Atlantic cod Gadus morhua.

    Science.gov (United States)

    Beirão, J; Purchase, C F; Wringe, B F; Fleming, I A

    2015-07-01

    This study tested the hypothesis that the effects of Atlantic cod Gadus morhua ovarian fluid on sperm motility variables are population specific. Sperm from a northern G. morhua population were activated in the presence of ovarian fluid from either northern or southern G. morhua at different concentrations. Ovarian fluid acted as a filter, in some cases reducing sperm swimming performance compared with seawater. Fluid from females foreign in population (southern) to the males (northern) had a greater inhibiting effect than those from the native population. Follow-up analysis indicated that the ovarian fluids had lower Ca(2+) concentration in northern than southern G. morhua, which could be the causative mechanism. If widespread, such cryptic female choice could reduce the incidence of intraspecific hybridization among diverged populations and contribute to reproductive isolation. © 2015 The Fisheries Society of the British Isles.

  2. Macro and trace elements in Paracentrotus lividus gonads from South West Atlantic areas

    DEFF Research Database (Denmark)

    Camacho, Carolina; Rocha, A. Cristina; Barbosa, Vera L.

    2018-01-01

    Sea urchin represents one of the most valuable seafood product being harvested and explored for their edible part, the gonads or roe. This species is generally considered a sentinel organism for ecotoxicological studies being widely used in monitoring programs to assess coastal aquatic environments...... three South West Atlantic production areas subjected to distinct environmental and anthropogenic pressures. In all studied areas, the elements profile in sea urchin gonads was Cl > K > P > Ca > S > Zn > Br > Fe > Sr > I > Rb > Cu > Se > Cr > Ni, suggesting an element guide profile with special interest...... for sea urchin farming development. Concerning toxic elements, the profile was the following: As > Cd > Pb > Hg > iAs. The results evidenced higher levels of Pb and Hg in open areas. Distinct area characteristics and anthropogenic pressures of production areas evidence the importance of biomonitoring...

  3. Atlantic water transformation and transport to the Arctic Ocean in the Fram Strait and Barents Sea Branches

    Science.gov (United States)

    Beszczynska-Möller, Agnieszka; Skagseth, Øystein; Walczowski, Waldemar; Lien, Vidar; von Appen, Wilken-Jon

    2017-04-01

    The heat content in the Arctic Ocean is to a large extent determined by oceanic advection from the south. During the last two decades the extraordinary warm Atlantic water (AW) inflow has been reported to progress through the Nordic Seas towards the Arctic Ocean. The ultimate fate of warm anomalies of Atlantic origin depends strongly on splitting of the AW flow into the Fram Strait (FSB) and Barents Sea Branch (BSB). Subsequent transformation of AW along these two branches and their relative strength govern the oceanic heat transport into the Arctic Ocean. Atlantic water, which leaves through Fram Strait with temperature of 3-3.5°C, brings between 26 and 50 TW of heat into the Arctic Ocean. Atlantic water inflow to the Barents Sea is warmer (6-6.5°C) and carries oceanic heat of a similar order, but most of it is lost to the atmosphere and sea ice melt before strongly modified AW enters the Arctic Ocean through the Barents Sea northern exit. In recent decades a significant warming and high variability of AW volume transport was observed in the both branches of Atlantic inflow. AW flow in the Barents Sea Branch is controlled by the strength of atmospheric low over the northern Barents Sea, acting through a wind-induced Ekman divergence, which intensifies eastward barotropic current. Transport in the Fram Strait Branch is mainly forced by the large-scale low-pressure system over the eastern Norwegian-Greenland Seas, which strengthens the coherent shelf break current along the eastern rim of the Nordic Seas. However, long-term moored observations in the Barents Sea Opening and the northern Fram Strait reveal that Atlantic water transport in both branches vary with the opposite phase on the inter-annual time scale. This suggests that in the periods of weaker Atlantic water flow in the shelf break current, the increased transport in the Barents Sea Branch can also further weaken the Fram Strait Branch. The anomalously warm AW inflow in the Fram Strait Branch has a

  4. Pre-anaesthetic metomidate sedation delays the stress response after caudal artery cannulation in Atlantic cod (Gadus morhua).

    Science.gov (United States)

    Karlsson, Anders; Rosseland, Bjørn Olav; Massabuau, Jean-Charles; Kiessling, Anders

    2012-04-01

    Recovery from caudal artery cannulation with and without pre-anaesthesia metomidate sedation was assessed in Atlantic cod (Gadus morhua). The levels of plasma cortisol, glucose, electrolytes and acid-base parameters were compared between sedated and unsedated cod and to those in uncannulated individuals, where the samples were obtained by sacrificial sampling (reference level). Metomidate sedation delayed the stress response, causing sedated cod plasma cortisol to return to the reference level more slowly [day 4 post surgery (PS)] than in unsedated cod (day 2 PS). Plasma glucose was elevated in both sedated and unsedated cod up to and including day 5 PS. Plasma K(+) was lower and pH was higher in cannulated cod than in the reference from 24 h PS until the end of experimentation, indicating a stress effect of sacrificial sampling on plasma K(+) and pH that was likely caused by an acute stress response. Metomidate sedation delayed the stress response following CA cannulation and should therefore not be used as a pre-anaesthetic sedation in Atlantic cod. The caudal artery cannulation can be a useful tool in obtaining repeated blood samples from Atlantic cod given an adequate recovery time, which was determined to be 6 days irrespective of pre-anaesthesia sedation status.

  5. Mid-Atlantic Wind - Overcoming the Challenges

    Energy Technology Data Exchange (ETDEWEB)

    Daniel F. Ancona III; Kathryn E. George; Lynn Sparling; Bruce C. Buckheit; Daniel LoBue; and Richard P. Bowers

    2012-06-29

    This study, supported by the US Department of Energy, Wind Powering America Program, Maryland Department of Natural Resources and Chesapeake Bay Foundation, analyzed barriers to wind energy development in the Mid-Atlantic region along with options for overcoming or mitigating them. The Mid-Atlantic States including Delaware, Maryland, North Carolina and Virginia, have excellent wind energy potential and growing demand for electricity, but only two utility-scale projects have been installed to date. Reasons for this apathetic development of wind resources were analyzed and quantified for four markets. Specific applications are: 1) Appalachian mountain ridgeline sites, 2) on coastal plains and peninsulas, 3) at shallow water sites in Delaware and Chesapeake Bays, Albemarle and Pamlico Sounds, and 4) at deeper water sites off the Atlantic coast. Each market has distinctly different opportunities and barriers. The primary barriers to wind development described in this report can be grouped into four categories; state policy and regulatory issues, wind resource technical uncertainty, economic viability, and public interest in environmental issues. The properties of these typologies are not mutually independent and do interact. The report concluded that there are no insurmountable barriers to land-based wind energy projects and they could be economically viable today. Likewise potential sites in sheltered shallow waters in regional bay and sounds have been largely overlooked but could be viable currently. Offshore ocean-based applications face higher costs and technical and wind resource uncertainties. The ongoing research and development program, revision of state incentive policies, additional wind measurement efforts, transmission system expansion, environmental baseline studies and outreach to private developers and stakeholders are needed to reduce barriers to wind energy development.

  6. Mid-Atlantic Wind - Overcoming the Challenges

    Energy Technology Data Exchange (ETDEWEB)

    Daniel F. Ancona III; Kathryn E. George; Richard P. Bowers; Dr. Lynn Sparling; Bruce Buckheit; Daniel LoBue

    2012-05-31

    This study, supported by the US Department of Energy, Wind Powering America Program, Maryland Department of Natural Resources and Chesapeake Bay Foundation, analyzed barriers to wind energy development in the Mid-Atlantic region along with options for overcoming or mitigating them. The Mid-Atlantic States including Delaware, Maryland, North Carolina and Virginia, have excellent wind energy potential and growing demand for electricity, but only two utility-scale projects have been installed to date. Reasons for this apathetic development of wind resources were analyzed and quantified for four markets. Specific applications are: 1) Appalachian mountain ridgeline sites, 2) on coastal plains and peninsulas, 3) at shallow water sites in Delaware and Chesapeake Bays, Albemarle and Pamlico Sounds, and 4) at deeper water sites off the Atlantic coast. Each market has distinctly different opportunities and barriers. The primary barriers to wind development described in this report can be grouped into four categories; state policy and regulatory issues, wind resource technical uncertainty, economic viability, and public interest in environmental issues. The properties of these typologies are not mutually independent and do interact. The report concluded that there are no insurmountable barriers to land-based wind energy projects and they could be economically viable today. Likewise potential sites in sheltered shallow waters in regional bay and sounds have been largely overlooked but could be viable currently. Offshore ocean-based applications face higher costs and technical and wind resource uncertainties. The ongoing research and development program, revision of state incentive policies, additional wind measurement efforts, transmission system expansion, environmental baseline studies and outreach to private developers and stakeholders are needed to reduce barriers to wind energy development.

  7. Characterizing the Variations of the motion of the North Atlantic tropical cyclones

    Science.gov (United States)

    Laurencin, Chelsey Nakita; Misra, Vasubandhu

    2017-11-01

    In this study, we examine the seasonal and interannual variability of the North Atlantic (NATL) tropical cyclone (TC) motion from the historical Hurricane Database (HURDAT2) over the period 1988-2014. We characterize these motions based on their position, lifecycle, and seasonal cycle. The main findings of this study include: (1) of the 11,469 NATL TC fixes examined between 1988 and 2014, 81% of them had a translation speed of 40 mph) are exclusively found north of 30 N, the slow-moving TCs have a wide range of latitude. This is largely a consequence of the background steering flow being weaker (stronger) in the tropical (higher) latitudes with a minimum around the subtropical latitudes of NATL; (3) there is an overall decrease in the frequency of all categories of translation speed of TCs in warm relative to cold El Niño Southern Oscillation (ENSO) years. However, in terms of the percentage change, TCs with a translation speed in the range of 10-20 mph display the most change (42%) in warm relative to cold ENSO years; and (4) there is an overall decrease in frequency across all categories of TC translation speed in small relative to large Atlantic Warm Pool years, but in terms of percentage change in the frequency of TCs, there is a significant and comparable change in the frequency over a wider range of translation speeds than the ENSO composites. This last finding suggests that Atlantic Warm Pool variations have a more profound impact on the translation speed of Atlantic TCs than ENSO.

  8. Modelling the chemically aged and mixed aerosols over the eastern central Atlantic Ocean – potential impacts

    Directory of Open Access Journals (Sweden)

    M. Astitha

    2010-07-01

    Full Text Available Detailed information on the chemical and physical properties of aerosols is important for assessing their role in air quality and climate. This work explores the origin and fate of continental aerosols transported over the Central Atlantic Ocean, in terms of chemical composition, number and size distribution, using chemistry-transport models, satellite data and in situ measurements. We focus on August 2005, a period with intense hurricane and tropical storm activity over the Atlantic Ocean. A mixture of anthropogenic (sulphates, nitrates, natural (desert dust, sea salt and chemically aged (sulphate and nitrate on dust aerosols is found entering the hurricane genesis region, most likely interacting with clouds in the area. Results from our modelling study suggest rather small amounts of accumulation mode desert dust, sea salt and chemically aged dust aerosols in this Atlantic Ocean region. Aerosols of smaller size (Aitken mode are more abundant in the area and in some occasions sulphates of anthropogenic origin and desert dust are of the same magnitude in terms of number concentrations. Typical aerosol number concentrations are derived for the vertical layers near shallow cloud formation regimes, indicating that the aerosol number concentration can reach several thousand particles per cubic centimetre. The vertical distribution of the aerosols shows that the desert dust particles are often transported near the top of the marine cloud layer as they enter into the region where deep convection is initiated. The anthropogenic sulphate aerosol can be transported within a thick layer and enter the cloud deck through multiple ways (from the top, the base of the cloud, and by entrainment. The sodium (sea salt related aerosol is mostly found below the cloud base. The results of this work may provide insights relevant for studies that consider aerosol influences on cloud processes and storm development in the Central Atlantic region.

  9. Differential response of corals to regional mass-warming events as evident from skeletal Sr/Ca and Mg/Ca ratios

    Science.gov (United States)

    Clarke, Harry; D'Olivo, Juan Pablo; Falter, James; Zinke, Jens; Lowe, Ryan; McCulloch, Malcolm

    2017-05-01

    During the summer of 2010/2011, a regional marine heat wave resulted in coral bleaching of variable severity along much of the western coastline of Australia. At Ningaloo Reef, a 300 km long fringing reef system and World Heritage site, highly contrasting coral bleaching was observed between two morphologically distinct nearshore reef communities located on either side of the Ningaloo Peninsula: Tantabiddi (˜20% bleaching) and Bundegi (˜90% bleaching). For this study, we collected coral cores (Porites sp.) from Tantabiddi and Bundegi reef sites to assess the response of the Sr/Ca temperature proxy and Mg/Ca ratios to the variable levels of thermal stress imposed at these two sites during the 2010/2011 warming event. We found that there was an anomalous increase in Sr/Ca and decrease in Mg/Ca ratios in the Bundegi record that was coincident with the timing of severe coral bleaching at the site, while no significant changes were observed in the Tantabiddi record. We show that the change in the relationship of Sr/Ca and Mg/Ca ratios with temperature at Bundegi during the 2010/2011 event reflects changes in related coral "vital" processes during periods of environmental stress. These changes were found to be consistent with a reduction in active transport of Ca2+ to the site of calcification leading to a reduction in calcification rates and reduced Rayleigh fractionation of incorporated trace elements.

  10. Scientific heritage of Alexandru Roşca: publications, spider collection, described species

    Directory of Open Access Journals (Sweden)

    Fedoriak, Mariia

    2016-04-01

    During the period 1931–1939, Roşca described 13 spider species. To date, five species names have been synonymised. We propose that six species should be treated as nomina dubia because of their poor descriptions and lack of availability of types and/or other specimens. For two of Roşca’s species, Pardosa roscai (Roewer, 1951 and Tetragnatha reimoseri (Roşca, 1939, data and figures are presented and information on them is updated.

  11. ruberculous Peritonitis with Perforation - Ca

    African Journals Online (AJOL)

    BOX 3409, Nairobi, KENYA. Int. 'luberculous peritonitis is a diagnostic dilemma in that there in no available diagnostic method of confirming ... The minimum period for treatment to be able to dose a perforation is in the range of 6 to 8 weeks. ... been treated for various illnesses including typhoid and peptic ulcer disease.

  12. Protein Phosphatase 2A Dephosphorylates CaBP4 and Regulates CaBP4 Function

    Science.gov (United States)

    Haeseleer, Françoise; Sokal, Izabela; Gregory, Frederick D.; Lee, Amy

    2013-01-01

    Purpose. CaBP4 is a neuronal Ca2+-binding protein that is expressed in the retina and in the cochlea, and is essential for normal photoreceptor synaptic function. CaBP4 is phosphorylated by protein kinase C zeta (PKCζ) in the retina at serine 37, which affects its interaction with and modulation of voltage-gated Cav1 Ca2+ channels. In this study, we investigated the potential role and functional significance of protein phosphatase 2A (PP2A) in CaBP4 dephosphorylation. Methods. The effect of protein phosphatase inhibitors, light, and overexpression of PP2A subunits on CaBP4 dephosphorylation was measured in in vitro assays. Pull-down experiments using retinal or transfected HEK293 cell lysates were used to investigate the association between CaBP4 and PP2A subunits. Electrophysiologic recordings of cotransfected HEK293 cells were performed to analyze the effect of CaBP4 dephosphorylation in modulating Cav1.3 currents. Results. PP2A inhibitors, okadaic acid (OA), and fostriecin, but not PP1 selective inhibitors, NIPP-1, and inhibitor 2, block CaBP4 dephosphorylation in retinal lysates. Increased phosphatase activity in light-dependent conditions reverses phosphorylation of CaBP4 by PKCζ. In HEK293 cells, overexpression of PP2A enhances the rate of dephosphorylation of CaBP4. In addition, inhibition of protein phosphatase activity by OA increases CaBP4 phosphorylation and potentiates the modulatory effect of CaBP4 on Cav1.3 Ca2+ channels in HEK293T cells. Conclusions. This study provides evidence that CaBP4 is dephosphorylated by PP2A in the retina. Our findings reveal a novel role for protein phosphatases in regulating CaBP4 function in the retina, which may fine tune presynaptic Ca2+ signals at the photoreceptor synapse. PMID:23341017

  13. Supralinear dendritic Ca2+ signalling in young developing CA1 pyramidal cells

    Science.gov (United States)

    Pohle, Jörg; Bischofberger, Josef

    2014-01-01

    Although Ca2+ is critically important in activity-dependent neuronal development, not much is known about the regulation of dendritic Ca2+ signals in developing neurons. Here, we used ratiometric Ca2+ imaging to investigate dendritic Ca2+ signalling in rat hippocampal pyramidal cells during the first 1–4 weeks of postnatal development. We show that active dendritic backpropagation of Nav channel-dependent action potentials (APs) evoked already large dendritic Ca2+ transients in animals aged 1 week with amplitudes of ∼150 nm, similar to the amplitudes of ∼160 nM seen in animals aged 4 weeks. Although the AP-evoked dendritic Ca2+ load increased about four times during the first 4 weeks, the peak amplitude of free Ca2+ concentration was balanced by a four-fold increase in Ca2+ buffer capacity κs (∼70 vs. ∼280). Furthermore, Ca2+ extrusion rates increased with postnatal development, leading to a slower decay time course (∼0.2 s vs. ∼0.1 s) and more effective temporal summation of Ca2+ signals in young cells. Most importantly, during prolonged theta-burst stimulation dendritic Ca2+ signals were up to three times larger in cells at 1 week than at 4 weeks of age and much larger than predicted by linear summation, which is attributable to an activity-dependent slow-down of Ca2+ extrusion. As Ca2+ influx is four-fold smaller in young cells, the larger Ca2+ signals are generated using four times less ATP consumption. Taken together, the data suggest that active backpropagations regulate dendritic Ca2+ signals during early postnatal development. Remarkably, during prolonged AP firing, Ca2+ signals are several times larger in young than in mature cells as a result of activity-dependent regulation of Ca2+ extrusion rates. PMID:25239458

  14. Property changes of deep and bottom waters in the Western Tropical Atlantic

    Science.gov (United States)

    Herrford, Josefine; Brandt, Peter; Zenk, Walter

    2017-06-01

    The flow of North Atlantic Deep Water (NADW) and Antarctic Bottom Water (AABW) contributes to the Atlantic meridional overturning circulation. Changes in the associated water mass formation might impact the deep ocean's capacity to take up anthropogenic CO2 while a warming of the deep ocean significantly contributes to global sea level rise. Here we compile historic and recent shipboard measurements of hydrography and velocity to provide a comprehensive view of water mass distribution, pathways, along-path transformation and long-term temperature changes of NADW and AABW in the western South and Equatorial Atlantic. We confirm previous results which show that the northwest corner of the Brazil Basin represents a splitting point for the southward/northward flow of NADW/AABW. The available measurements sample water mass transformation along the two major routes for deep and bottom waters in the tropical to South Atlantic - along the deep western boundary and eastward, parallel to the equator - as well as the hot-spots of extensive mixing. We find lower NADW and lighter AABW to form a highly interactive transition layer in the northern Brazil Basin. The AABW north of 5°S is relatively homogeneous with only lighter AABW being able to pass through the Equatorial Channel (EQCH) into the North Atlantic. Spanning a period of 26 years, our data also allow an estimation of long-term temperature trends in abyssal waters. We find a warming of 2.5±0.7•10-3 °C yr-1 of the waters in the northern Brazil Basin at temperatures colder than 0.6 °C throughout the period 1989-2014 and can relate this warming to a thinning of the dense AABW layer. Whereas isopycnal heave is the dominant effect which defines the vertical distribution of temperature trends on isobars, we also find temperature changes on isopycnals in the lower NADW and AABW layers. There temperatures on isopycnals exhibit decadal variations with warming in the 1990s and cooling in the 2000s - the contributions to the

  15. Tectonic forcing of early to middle jurassic seawater Sr/Ca

    DEFF Research Database (Denmark)

    Ullmann, Clemens Vinzenz; Hesselbo, Stephen P.; Korte, Christoph

    2013-01-01

    The Jurassic Period (ca. 201–145 Ma) is marked by fundamental reorganizations of paleogeography, paleoceanography, ecosystems, and the progressive shift from aragonite to calcite as the favored marine biogenic carbonate polymorph. Sr/Ca ratios of well-preserved Jurassic oysters and belemnites from...... sections in the UK and Poland demonstrate that the Sr/Ca ratio of seawater varied systematically throughout the Early and Middle Jurassic in parallel with already documented seawater 87Sr/86Sr. The Sr flux from increased mid-ocean ridge activity in the Early Jurassic outbalanced the input of riverine Sr...

  16. Role of the North Atlantic Oscillation in decadal temperature trends

    Science.gov (United States)

    Iles, Carley; Hegerl, Gabriele

    2017-11-01

    Global temperatures have undergone periods of enhanced warming and pauses over the last century, with greater variations at local scales due to internal variability of the climate system. Here we investigate the role of the North Atlantic Oscillation (NAO) in decadal temperature trends in the Northern Hemisphere for periods with large decadal NAO trends. Using a regression based technique we find a best estimate that trends in the NAO more than halved (reduced by 57%, 5%–95%: 47%–63%) the winter warming over the Northern Hemisphere extratropics (NH; 30N–90N) from 1920–1971 and account for 45% (±14%) of the warming there from 1963–1995, with larger impacts on regional scales. Over the period leading into the so-called warming hiatus, 1989–2013, the NAO reduced NH winter warming to around one quarter (24%; 19%–31%) of what it would have been, and caused large negative regional trends, for example, in Northern Eurasia. Warming is more spatially uniform across the Northern Hemisphere after removing the NAO influence in winter, and agreement with multi-model mean simulated trends improves. The impact of the summer NAO is much weaker, but still discernible over Europe, North America and Greenland, with the downward trend in the summer NAO from 1988–2012 reducing warming by about a third in Northern Europe and a half in North America. A composite analysis using CMIP5 control runs suggests that the ocean response to prolonged NAO trends may increase the influence of decadal NAO trends compared to estimates based on interannual regressions, particularly in the Arctic. Results imply that the long-term NAO trends over the 20th century alternately masked or enhanced anthropogenic warming, and will continue to temporarily offset or enhance its effects in the future.

  17. Assessing the impact of swimming exercise and the relative susceptibility of rainbow trout oncorhynchus mykiss (walbaum) and atlantic salmon salmo salar L. following injection challenge with weissella ceti

    Science.gov (United States)

    All-female rainbow trout and mixed-sex Atlantic salmon (approximately 200 g and 120 g initial weight, respectively) were maintained in small circular tanks in a flow-through system under study conditions for a period of five months. The four tank populations consisted of rainbow trout exposed to ei...

  18. δ13C decreases in the upper western South Atlantic during Heinrich Stadials 3 and 2

    Science.gov (United States)

    Campos, Marília C.; Chiessi, Cristiano M.; Voigt, Ines; Piola, Alberto R.; Kuhnert, Henning; Mulitza, Stefan

    2017-04-01

    Abrupt millennial-scale climate change events of the last deglaciation (i.e. Heinrich Stadial 1 and the Younger Dryas) were accompanied by marked increases in atmospheric CO2 (CO2atm) and decreases in its stable carbon isotopic ratios (δ13C), i.e. δ13CO2atm, presumably due to outgassing from the ocean. However, information on the preceding Heinrich Stadials during the last glacial period is scarce. Here we present δ13C records from two species of planktonic foraminifera from the western South Atlantic that reveal major decreases (up to 1 ‰) during Heinrich Stadials 3 and 2. These δ13C decreases are most likely related to millennial-scale periods of weakening of the Atlantic meridional overturning circulation and the consequent increase (decrease) in CO2atm (δ13CO2atm). We hypothesise two mechanisms that could account for the decreases observed in our records, namely strengthening of Southern Ocean deep-water ventilation and weakening of the biological pump. Additionally, we suggest that air-sea gas exchange could have contributed to the observed δ13C decreases. Together with other lines of evidence, our data are consistent with the hypothesis that the CO2 added to the atmosphere during abrupt millennial-scale climate change events of the last glacial period also originated in the ocean and reached the atmosphere by outgassing. The temporal evolution of δ13C during Heinrich Stadials 3 and 2 in our records is characterized by two relative minima separated by a relative maximum. This w structure is also found in North Atlantic and South American records, further suggesting that such a structure is a pervasive feature of Heinrich Stadial 2 and, possibly, also Heinrich Stadial 3.

  19. A 3000-year annual-resolution record of the North Atlantic Oscillation

    Science.gov (United States)

    Kelly, B. F.; Mariethoz, G.; Hellstrom, J.; Baker, A.

    2013-12-01

    The North Atlantic Oscillation provides an index of North Atlantic climate variability. The 947-yr long annual resolution record of the North Atlantic Oscillation (NAO) of Trouet et al. (2009, Science, 324, 78-81), the NAO Morocco-Scotland index, combined tree ring and stalagmite data, the latter a single stalagmite growth rate archive from NW Scotland. Trouet et al (2009) noted the unusual persistence of the positive phase of the NAO during the Medieval Climate Anomaly (MCA; 1050-1400AD). In order to better assess the uniqueness of the persistently positive NAO in the MCA, we extend the speleothem portion of the proxy NAO record with a composite of five stalagmites from the same cave system. We present the first-ever composite speleothem growth rate record. Using a combination of lamina counting, U-Th dating, and correlation between growth rate series, we build a continuous, annual-resolution, annually laminated, stalagmite growth rates series for the last 3000 years. We use geostatistical and stochastic approaches appropriate to stalagmite growth rate time series to characterise uncertainty in the stalagmite series and to screen them for periods of relative climate sensitivity vs. periods where there is hydrologically introduced, non-climatic variability. We produce the longest annual-resolution annual lamina record of the NAO for the last 3000 years. The screened stalagmite series is compared to instrumental and proxy records of the NAO. Spectral and wavelet analysis demonstrates that the series contains significant decadal to centennial scale periodicity throughout the record. We demonstrate that the persistently positive NAO during the MCA (1080-1460 CE) is remarkable within the last 3000 years. Two other phases of persistent, positive NAO, occur at 290-550 CE and 660-530 BCE, in agreement with the lower resolution, 5,200-yr Greenland lake sediment NAO proxy (Olsen et al, 2012, Nature Geoscience, 5, 808-812).

  20. Climate reconstruction for the last two millennia in central Iberia: The role of East Atlantic (EA), North Atlantic Oscillation (NAO) and their interplay over the Iberian Peninsula

    Science.gov (United States)

    Sánchez-López, G.; Hernández, A.; Pla-Rabes, S.; Trigo, R. M.; Toro, M.; Granados, I.; Sáez, A.; Masqué, P.; Pueyo, J. J.; Rubio-Inglés, M. J.; Giralt, S.

    2016-10-01

    A multi-proxy characterization of the uppermost sedimentary infill of an Iberian alpine lake (Cimera, 2140 m a.s.l.) was performed to establish the climatic and environmental conditions for the Iberian Central Range (ICR) over the last two millennia. This multi-proxy characterization was used to reconstruct the intense runoff events, lake productivity and soil erosion in the lake catchment and interpret these factors in terms of temperature and precipitation variability. The Roman Period (RP; 200 BCE - 500 CE) beginning was characterized by an alternation between cold and warm periods as indicated by short-lived oscillations of intense runoff conditions and soil erosion, although warm conditions dominated the end of the period and the Early Middle Age (EMA; 500-900 CE) onset in the ICR. A noticeable decrease in intense runoff events and a progressive decrease in soil erosion during the late EMA indicated a shift to colder temperatures. In terms of precipitation, both the RP and EMA climate periods displayed a transition from dry to wet conditions that led to a decrease in lake productivity. The Medieval Climate Anomaly (MCA; 900-1300 CE) was characterized by warm and dry conditions with frequent intense runoff episodes and increases in lake productivity and soil erosion, whereas the Little Ice Age (LIA; 1300-1850 CE) showed the opposite characteristics. The Industrial Era (1850-2012 CE) presented an increase in lake productivity that likely demonstrates the influence of global warming. The spatio-temporal integration of the Cimera record with other Iberian reconstructions has been used to identify the main climate drivers over this region. During the RP and EMA, N-S and E-W humidity gradients were dominant, whereas during the MCA and LIA, these gradients were not evident. These differences could be ascribed to interactions between the North Atlantic Oscillation (NAO) and East Atlantic (EA) phases. During the RP, the general warm conditions and the E-W humidity

  1. Reproducibility of Clathromorphum compactum coralline algal Mg/Ca ratios and comparison to high-resolution sea surface temperature data

    Science.gov (United States)

    Hetzinger, S.; Halfar, J.; Kronz, A.; Simon, K.; Adey, W. H.; Steneck, R. S.

    2018-01-01

    The potential of crustose coralline algae as high-resolution archives of past ocean variability in mid- to high-latitudes has only recently been recognized. Few comparisons of coralline algal proxies, such as temperature-dependent algal magnesium to calcium (Mg/Ca) ratios, with in situ-measured surface ocean data exist, even rarer are well replicated records from individual sites. We present Mg/Ca records from nine coralline algal specimens (Clathromorphum compactum) from a single site in the Gulf of Maine, North Atlantic. Sections from algal mounds were analyzed using Laser Ablation-Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) yielding individual Mg/Ca records of up to 30 years in length. We first test intra- and intersample signal replication and show that algal Mg/Ca ratios are reproducible along several transects within individual sample specimens and between different samples from the same study site. In addition, LA-ICP-MS-derived Mg/Ca ratios are compared to electron microprobe (EMP) analyzed data on the longest-lived specimens and were found to be statistically commensurable. Second, we evaluate whether relationships between algal-based SST reconstructions and in situ temperature data can be improved by averaging Mg/Ca records from multiple algal specimens (intersample averages). We found that intersample averages yield stronger relationships to sea surface temperature (SST) data than Mg/Ca records derived from individual samples alone. Thus, Mg/Ca-based paleotemperature reconstructions from coralline algae can benefit from using multiple samples per site, and can expand temperature proxy precision from seasonal to monthly.

  2. Automated analysis of calcium spiking profiles with CaSA software: two case studies from root-microbe symbioses.

    Science.gov (United States)

    Russo, Giulia; Spinella, Salvatore; Sciacca, Eva; Bonfante, Paola; Genre, Andrea

    2013-12-26

    Repeated oscillations in intracellular calcium (Ca2+) concentration, known as Ca2+ spiking signals, have been described in plants for a limited number of cellular responses to biotic or abiotic stimuli and most notably the common symbiotic signaling pathway (CSSP) which mediates the recognition by their plant hosts of two endosymbiotic microbes, arbuscular mycorrhizal (AM) fungi and nitrogen fixing rhizobia. The detailed analysis of the complexity and variability of the Ca2+ spiking patterns which have been revealed in recent studies requires both extensive datasets and sophisticated statistical tools. As a contribution, we have developed automated Ca2+ spiking analysis (CaSA) software that performs i) automated peak detection, ii) statistical analyses based on the detected peaks, iii) autocorrelation analysis of peak-to-peak intervals to highlight major traits in the spiking pattern.We have evaluated CaSA in two experimental studies. In the first, CaSA highlighted unpredicted differences in the spiking patterns induced in Medicago truncatula root epidermal cells by exudates of the AM fungus Gigaspora margarita as a function of the phosphate concentration in the growth medium of both host and fungus. In the second study we compared the spiking patterns triggered by either AM fungal or rhizobial symbiotic signals. CaSA revealed the existence of different patterns in signal periodicity, which are thought to contribute to the so-called Ca2+ signature. We therefore propose CaSA as a useful tool for characterizing oscillatory biological phenomena such as Ca2+ spiking.

  3. Multi-decadal-scale records of North Atlantic climate variability during the last and present interglacials: Climate sensitivity and the AMOC

    Science.gov (United States)

    Jimenez-Amat, P.; Zahn, R.; Martrat, B.; Grimalt, J. O.

    2012-12-01

    North Atlantic climate sensitivity plays a crucial role in understanding current and future developments of the Atlantic meridional overturning circulation (AMOC). A shifted configuration of Earth's orbital parameters about the Sun caused an approximate 3% higher radiative forcing during the Last Interglacial (LIG, MIS5e; 129-115kyr) and drove climate to measurably warmer conditions than during the Present Interglacial (PIG, Holocene, 11-0Kyr). Paleoceanographic time series of surface ocean climatology from Ocean Drilling Program (ODP) Site 976 in the Alboran Sea, westernmost Mediterranean, reflect the climatic variability during the LIG and PIG. The site receives climate signals from the advection of Atlantic inflow waters confirming its quality to monitor North Atlantic climate variability. Elevated rates of sedimentation deposition at the site enable resolving variability at multi-decadal resolution (60-90 yrs). Sea surface temperature (SST) time series were established from element concentrations (Mg/Ca) in the planktonic foraminifera Globigerina bulloides. SST from alkenones were also measured for comparison purposes. Planktonic oxygen isotopes from G. bulloides allow direct comparison with speleothems and ice cores. LIG SST are between 3°- 6°C warmer than PIG SST and multi-decadal-scale variability by 4°C and more is indicated by highly variable Mg/Ca ratios. This variability persisted during the LIG climatic optimum, confirming that SST and climatic variability were independent of large ice sheets. The high variability is contrasted by more stable SST in the Uk37-derived SST record, plausibly alluding to differential SST recording by the molecular biomarker proxy. Correlation with δ18O records from European speleothems suggests the SST pattern reflects climate of the western North Atlantic region. The LIG SST pattern at ODP 976 differs from that at open North Atlantic settings where maximum SST during the LIG climatic optimum remained some 6°C below

  4. Reconstruction of the North Atlantic end-member of the thermohaline circulation across the Mid-Pleistocene Transition

    Science.gov (United States)

    Kim, J.; Seguí, M. J.; Yehudai, M.; Goldstein, S. L.; Pena, L. D.; Raymo, M. E.; Ford, H. L.; Haynes, L.; Farmer, J. R.; Hoenisch, B.

    2016-12-01

    The dominant periodicity of glacial and interglacial cycles shifted from 41 ky to 100 ky at 1.2-0.8 Ma, marking the Mid-Pleistocene Transition (MPT). Pena and Goldstein (Science, 2014) investigated changes in the Earth's global thermohaline circulation (THC), focusing on South Atlantic cores, and concluded that the THC experienced major disruptions between 950-850 ka (MIS 25 to 21), which generated the climatic conditions that intensified cold periods, prolonged their duration, and stabilized 100 ky cycles. However, knowledge of the coeval North Atlantic is key for interpreting data from the Middle and South Atlantic. We report Nd isotope ratios on Fe-Mn oxide encrusted foraminifera and fish debris from DSDP Site 607 (41.001N; 32.957W, 3427m) between 1.2-0.4 Ma, as a representative of the deep North Atlantic. Pre-MPT results (MIS 35-25) show interglacial ɛNd-values of -13.5 to -14.0, similar to today, and glacial-interglacial variability of 1 ɛNd-unit. Post-MPT results after MIS 19 also show interglacial ɛNd-values of -13.5 to -14.0, but greater glacial-interglacial variability of 2 ɛNd-units. Interglacial-to-glacial transitions throughout the core shift to higher ɛNd-values indicative of weakening THC, except for MIS 26, which is uniquely more negative than the neighboring interglacials, with ɛNd reaching -14.5. During the critical MPT interval of MIS 25-21 recognized by Pena and Goldstein (2014), and continuing beyond it through MIS 19, DSDP 607 ɛNd shows higher values of -11.5 to -12.5, like post-MPT glacials. Thus for the North Atlantic, from the point of view of ɛNd in DSDP 607, post-MPT and pre-MPT interglacials are similar, and post-MPT glacials and MPT glacials are similar. Moreover, comparison to the Pena and Goldstein (2014) South Atlantic data indicates that disruptions to North Atlantic overturning may have begun as early as MIS 27, and the recovery to the pre-MPT interglacial conditions may have been delayed beyond MIS 19.

  5. [Childhood periodic syndromes].

    Science.gov (United States)

    Cuvellier, J-C; Lépine, A

    2010-01-01

    This review focuses on the so-called "periodic syndromes of childhood that are precursors to migraine", as included in the Second Edition of the International Classification of Headache Disorders. Three periodic syndromes of childhood are included in the Second Edition of the International Classification of Headache Disorders: abdominal migraine, cyclic vomiting syndrome and benign paroxysmal vertigo, and a fourth, benign paroxysmal torticollis is presented in the Appendix. The key clinical features of this group of disorders are the episodic pattern and intervals of complete health. Episodes of benign paroxysmal torticollis begin between 2 and 8 months of age. Attacks are characterized by an abnormal inclination and/or rotation of the head to one side, due to cervical dystonia. They usually resolve by 5 years. Benign paroxysmal vertigo presents as sudden attacks of vertigo, accompanied by inability to stand without support, and lasting seconds to minutes. Age at onset is between 2 and 4 years, and the symptoms disappear by the age of 5. Cyclic vomiting syndrome is characterized in young infants and children by repeated stereotyped episodes of pernicious vomiting, at times to the point of dehydration, and impacting quality of life. Mean age of onset is 5 years. Abdominal migraine remains a controversial issue and presents in childhood with repeated stereotyped episodes of unexplained abdominal pain, nausea and vomiting occurring in the absence of headache. Mean age of onset is 7 years. Both cyclic vomiting syndrome and abdominal migraine are noted for the absence of pathognomonic clinical features but also for the large number of other conditions to be considered in their differential diagnoses. Diagnostic criteria, such as those of the Second Edition of the International Classification of Headache Disorders and the North American Society for Pediatric Gastroenterology, Hepatology and Nutrition, have made diagnostic approach and management easier. Their diagnosis

  6. Accumulation and elimination of methylmercury in Atlantic cod (Gadus morhua L.) following dietary exposure

    Energy Technology Data Exchange (ETDEWEB)

    Amlund, Heidi [National Institute of Nutrition and Seafood Research (NIFES), P.O. Box 2029 Nordnes, 5817 Bergen (Norway)]. E-mail: heidi.amlund@nifes.no; Lundebye, Anne-Katrine [National Institute of Nutrition and Seafood Research (NIFES), P.O. Box 2029 Nordnes, 5817 Bergen (Norway); Berntssen, Marc H.G. [National Institute of Nutrition and Seafood Research (NIFES), P.O. Box 2029 Nordnes, 5817 Bergen (Norway)

    2007-08-01

    Methylmercury is known to bioaccumulate and biomagnify up the marine food chain. Fish from high levels of the marine food chain may contain relatively high concentrations of mercury, and most (>70%) of the mercury found in muscle is methylmercury. In aquaculture, marine protein (mainly fishmeal) is the dominant source of methylmercury, and this raises some concern with regards to fish welfare and consumer safety. A dietary exposure study, including a depuration period, was carried out in order to study the accumulation and elimination of methylmercury in Atlantic cod (Gadus morhua L.), and to estimate the transfer of methylmercury from feed to fish. Fish were sampled throughout a three month exposure period and a three month depuration period. Muscle samples were fractionated into a protein and a lipid fraction by lipid extraction using methanol and chloroform. Mercury and methylmercury were determined by inductively coupled plasma mass spectrometry (ICPMS) and gas chromatography-inductively coupled plasma mass spectrometry (GC-ICPMS), respectively. A continuous accumulation of methylmercury, after a lag period of 10 days, was observed in muscle tissue during the three months exposure to methylmercury (0.95+/-0.03{mu}g Hg/g feed, n=6). After three months, the final concentration in muscle was 0.38+/-0.04{mu}g Hg/gww (n=6), where methylmercury constituted 90-95% of the mercury present. The elimination of methylmercury from muscle was slow and incomplete (within the three months of depuration) with an estimated elimination half-life (t{sub 1/2}) of 377 days. The transfer of methylmercury from feed to Atlantic cod, described by the estimated absorption efficiency, was 38%. In muscle more than 99% of the mercury was found in the protein fraction. These results suggest that Atlantic cod readily takes up dietary methylmercury, which is efficiently accumulated into muscle, where it is incorporated into larger peptides or proteins. Comparable results were found for

  7. Natural Disasters in Southeastern Brazil Associated with the South Atlantic Convergence Zone

    Science.gov (United States)

    Teixeira Nery, Jonas; Malvestio, Leônidas

    2017-04-01

    This study analyzed rains in southeastern Brazil associated with the South Atlantic Convergence Zone (SACZ), which resulted in several disasters over the study area. The study period was from 1976 to 2010 and data were obtained from the National Water Agency (ANA) and Department of Water and Energy (DAEE) of the state of São Paulo. Outgoing Longwave Radiation (OLR) data were also used to analyze SACZ, which is an important dynamics influencing spring and summer in this region. A close relationship between SACZ intensity and economic and life losses in the study area was observed.

  8. Effect of Warm Atlantic Waters on the Climate Anomalies in the West Arctic

    Directory of Open Access Journals (Sweden)

    A. N. Zolotokrylin

    2015-01-01

    Full Text Available Significant climatic changes of oceanic and atmospheric elements and a relation of them to the ocean surface winter anomalies in North Atlantic are analyzed in the paper. Periods of «warm» ocean (2002–2012 and «cold» ocean (1960–1970 were determined. Positive anomalies of the ocean surface temperature increase the ice-free water area and, correspondingly, decrease the ice-field area. As a result of such changes in a state of the ocean surface (open water and ice, surface air temperature rises, and, consequently, atmospheric pressure in central part of a given Arctic sector drops.

  9. Synchronisation of palaeoenvironmental events in the North Atlantic region during the last termination

    DEFF Research Database (Denmark)

    Lowe, John J.; Rasmussen, Sune Olander; Björck, Svante

    2008-01-01

    protocol for time-stratigraphic correlation in the North Atlantic region over a more extended time period (30–8 ka). This employs the new NGRIP isotopic record and associated Greenland Ice Core Chronology 2005 (GICC05) as the regional stratotype, INTCAL04 for the calibration of radiocarbon dates, Bayesian...... of radiocarbon dates [Lowe, J.J., Hoek, W., INTIMATE Group, 2001. Inter-regional correlation of palaeoclimatic records for the Last Glacial-Interglacial Transition: a protocol for improved precision recommended by the INTIMATE project group. Quaternary Science Reviews 20, 1175–1187]. Here, we present a revised...

  10. 78 FR 53404 - Fisheries of the Northeastern United States; Atlantic Mackerel, Squid, and Butterfish Fisheries...

    Science.gov (United States)

    2013-08-29

    ... United States; Atlantic Mackerel, Squid, and Butterfish Fisheries; Amendment 14 AGENCY: National Marine... the Atlantic Mackerel, Squid and Butterfish Management Plan. The Mid-Atlantic Fishery Management Council developed Amendment 14 to improve catch monitoring for the Atlantic mackerel, squid, and...

  11. Fuzzy modelling of Atlantic salmon physical habitat

    Science.gov (United States)

    St-Hilaire, André; Mocq, Julien; Cunjak, Richard

    2015-04-01

    Fish habitat models typically attempt to quantify the amount of available river habitat for a given fish species for various flow and hydraulic conditions. To achieve this, information on the preferred range of values of key physical habitat variables (e.g. water level, velocity, substrate diameter) for the targeted fishs pecies need to be modelled. In this context, we developed several habitat suitability indices sets for three Atlantic salmon life stages (young-of-the-year (YOY), parr, spawning adults) with the help of fuzzy logic modeling. Using the knowledge of twenty-seven experts, from both sides of the Atlantic Ocean, we defined fuzzy sets of four variables (depth, substrate size, velocity and Habitat Suitability Index, or HSI) and associated fuzzy rules. When applied to the Romaine River (Canada), median curves of standardized Weighted Usable Area (WUA) were calculated and a confidence interval was obtained by bootstrap resampling. Despite the large range of WUA covered by the expert WUA curves, confidence intervals were relatively narrow: an average width of 0.095 (on a scale of 0 to 1) for spawning habitat, 0.155 for parr rearing habitat and 0.160 for YOY rearing habitat. When considering an environmental flow value corresponding to 90% of the maximum reached by WUA curve, results seem acceptable for the Romaine River. Generally, this proposed fuzzy logic method seems suitable to model habitat availability for the three life stages, while also providing an estimate of uncertainty in salmon preferences.

  12. Modelling of the North Atlantic eddy characteristics

    Science.gov (United States)

    Ushakov, Konstantin; Ibrayev, Rashit

    2017-04-01

    We investigate eddy characteristics of the Atlantic basin circulation and their impact on the ocean heat transport. A 15-year-long numerical experiment is performed with the global 3-dimensional z-coordinate INMIO ocean general circulation model of 0.1 deg., 49 levels resolution in conditions of the CORE-II protocol. The model is tuned to maximal intensity of eddies production by using only biharmonic filters instead of lateral viscous and diffusive terms in the model equations. Comparison with viscous and coarse-resolution simulations shows the increase of explicitly resolved heat transfer fraction and absolute values. Vertical turbulent mixing is parameterized by the Munk-Anderson scheme including convective adjustment. The sea ice is described by a simple thermodynamic submodel. The eddying velocity and temperature field components are defined as anomalies relative to the 3-month sliding mean. The regional distributions of hydrological parameters, eddy kinetic energy, heat convergence, meridional heat transport (MHT) and Atlantic meridional overturning circulation (AMOC) streamfunction, and their temporal variability are analyzed. In some parts of the basin the simulated eddy heat transport is opposite to the mean flow transport and may change direction with depth. The MHT intensity is slightly below observationally based assessments with notable influence of the East Greenland current simulation bias. The work is supported by the Russian Science Foundation (project N 14-27-00126) and performed in the Institute of Numerical Mathematics, Russian Academy of Sciences.

  13. Harvesting Atlantic Cod under Climate Variability

    Science.gov (United States)

    Oremus, K. L.

    2016-12-01

    Previous literature links the growth of a fishery to climate variability. This study uses an age-structured bioeconomic model to compare optimal harvest in the Gulf of Maine Atlantic cod fishery under a variable climate versus a static climate. The optimal harvest path depends on the relationship between fishery growth and the interest rate, with higher interest rates dictating greater harvests now at the cost of long-term stock sustainability. Given the time horizon of a single generation of fishermen under assumptions of a static climate, the model finds that the economically optimal management strategy is to harvest the entire stock in the short term and allow the fishery to collapse. However, if the biological growth of the fishery is assumed to vary with climate conditions, such as the North Atlantic Oscillation, there will always be pulses of high growth in the stock. During some of these high-growth years, the growth of the stock and its economic yield can exceed the growth rate of the economy even under high interest rates. This implies that it is not economically optimal to exhaust the New England cod fishery if NAO is included in the biological growth function. This finding may have theoretical implications for the management of other renewable yet exhaustible resources whose growth rates are subject to climate variability.

  14. Edges and Overlaps in Northwest Atlantic Phylogeography

    Directory of Open Access Journals (Sweden)

    James E. Byers

    2013-04-01

    Full Text Available As marine environments change, the greatest ecological shifts—including resource usage and species interactions—are likely to take place in or near regions of biogeographic and phylogeographic transition. However, our understanding of where these transitional regions exist depends on the defining criteria. Here we evaluate phylogeographic transitions using a bootstrapping procedure that allows us to focus on either the strongest genetic transitions between a pair of contiguous populations, versus evaluation of transitions inclusive of the entire overlap between two intraspecific genetic lineages. We compiled data for the Atlantic coast of the United States, and evaluate taxa with short- and long-dispersing larval phases separately. Our results are largely concordant with previous biogeographic and phylogeographic analyses, indicating strong biotic change associated with the regions near Cape Cod, the Delmarva Peninsula, and eastern Florida. However, inclusive analysis of the entire range of sympatry for intraspecific lineages suggests that broad regions—the Mid-Atlantic Bight and eastern Florida–already harbor divergent intraspecific lineages, suggesting the potential for ecological evaluation of resource use between these lineages. This study establishes baseline information for tracking how such patterns change as predicted environmental changes take place.

  15. The enigmatic whale: the North Atlantic humpback

    Directory of Open Access Journals (Sweden)

    Tim D Smith

    2009-09-01

    Full Text Available We know more about the North Atlantic humpback whale (Megaptera novaeangliae than we do for virtually any other cetacean, yet attempts to use this information to describe the status of the populations in this ocean basin have not proven satisfactory. The North Atlantic humpback has been the subject of extensive research over the past few decades, resulting in a substantial amount of knowledge about what has proven to be a species with a very complex life history and population structure. While several population models have been developed to integrate the available information, the data overall are not well described by any of the models. This has left considerable uncertainty about population status, and has raised questions about the interpretation of some of the data. We describe 7 specific areas where puzzling or ambiguous observations have been made; these require closer attention if population status is to be determined. These areas raise several fundamental questions, including: How many breeding populations are there? How much do the populations mix on the feeding grounds? How has the distribution of animals on both feeding and breeding grounds changed? We identify additional research needed to address the 7 areas and these questions in particular, so that population status might be determined.

  16. Exploring B/Ca as a pH proxy in bivalves: relationships between Mytilus californianus B/Ca and environmental data from the northeast Pacific

    Directory of Open Access Journals (Sweden)

    N. Shimizu

    2011-09-01

    Full Text Available A distinct gap in our ability to understand changes in coastal biology that may be associated with recent ocean acidification is the paucity of directly measured ocean environmental parameters at coastal sites in recent decades. Thus, many researchers have turned to sclerochronological reconstructions of water chemistry to document the historical seawater environment. In this study, we explore the relationships between B/Ca and pH to test the feasibility of B/Ca measured on the ion probe as a pH proxy in the California mussel, Mytilus californianus. Heterogeneity in a range of ion microprobe standards is assessed, leading to reproducible B/Ca ratios at the 5% level. The B/Ca data exhibit large excursions during winter months, which are particularly pronounced during the severe winters of 2004–2005 and 2005–2006. Furthermore, B/Ca ratios are offset in different parts of the skeleton that calcified at the same time. We compare the M. californianus B/Ca record to directly measured environmental data during mussel growth from the period of 1999–2009 to examine whether seawater chemistry or temperature plays a role in controlling shell B/Ca. A suite of growth rate models based on measured temperature are compared to the B/Ca data to optimise the potential fit of B/Ca to pH. Despite sampling conditions that were well-suited to testing a pH control on B/Ca, including a close proximity to an environmental record, a distinct change in pH at the sampling locale, and a growth model designed to optimise the correlations between seawater pH and shell B/Ca, we do not see a strong correlations between pH and shell B/Ca (maximum coefficient of determination, r2, of 0.207. Instead, our data indicate a strong biological control on B/Ca as observed in some other carbonate-forming organisms.

  17. Continental shelf processes affecting the oceanography of the South Atlantic Bight. Progress report

    Energy Technology Data Exchange (ETDEWEB)

    Pietrafesa, L.J.

    1978-03-01

    The objectives of the project were to determine the physical/dynamical processes controlling/affecting the distribution of phytoplankton nutrients on the continental shelf in the South Atlantic Bight. The initial objectives were to determine the short term, i.e., 2 to 10 day and longer term flux of nutrients onto the continental shelf. This is clearly related to the more general problem of combined physical and biogenic control of phytoplankton nutrients. During the period from June, 1975 to March, 1978 the study of the continental shelf processes affecting the oceanography of the South Atlantic Bight has been principally involved with a substantial, coordinated field effort. The success of the data acquisition phase of the program has now required an intensive data analysis phase which has been slowly increasing in effort. Emphasis is placed on the main phase of the field program, located in Onslow Bay, which has beel completed and the data are being analyzed. During the three-year period 20 cruises were made into the Carolina Capes area and samples were collected. A list is included of some 100 publications during the period.

  18. Ca(2+) signalling in the Golgi apparatus.

    Science.gov (United States)

    Pizzo, Paola; Lissandron, Valentina; Capitanio, Paola; Pozzan, Tullio

    2011-08-01

    The Golgi apparatus plays a central role in lipid and protein post-translational modification and sorting. Morphologically the organelle is heterogeneous and it is possible to distinguish stacks of flat cysternae (cis- and medial Golgi), tubular-reticular networks and vesicles (trans-Golgi). These morphological differences parallel a distinct functionality with a selective distribution and complementary roles of the enzymes found in the different compartments. The Golgi apparatus has been also shown to be involved in Ca(2+) signalling: it is indeed endowed with Ca(2+) pumps, Ca(2+) release channels and Ca(2+) binding proteins and is thought to participate in determining the spatio-temporal complexity of the Ca(2+) signal within the cell, though this role is still poorly understood. Recently, it has been demonstrated that the organelle is heterogeneous in terms of Ca(2+) handling and selective reduction of Ca(2+) concentration, both in vitro and in a genetic human disease, within one of its sub-compartment results in alterations of protein trafficking within the secretory pathway and of the entire Golgi morphology. In this paper we review the available information on the Ca(2+) toolkit within the Golgi, its heterogeneous distribution in the organelle sub-compartments and discuss the implications of these characteristics for the physiopathology of the Golgi apparatus. 2011 Elsevier Ltd. All rights reserved.

  19. Cuento: Sangre de caña

    Directory of Open Access Journals (Sweden)

    Segundo Benjamín Corredor

    1967-09-01

    Full Text Available El viento se convertía en murmullo contra las hojas de los cañaverales y contra los techos semipelados del rancho. También menguaba el calor que maduraba los plantíos de caña y que hacía más efusiva la sangre de los moradores.

  20. The delicate bistability of CaMKII.

    Science.gov (United States)

    Michalski, P J

    2013-08-06

    Calcium/calmodulin-dependent protein kinase II (CaMKII) is a synaptic, autophosphorylating kinase that is essential for learning and memory. Previous models have suggested that CaMKII functions as a bistable switch that could be the molecular correlate of long-term memory, but experiments have failed to validate these predictions. These models involved significant approximations to overcome the combinatorial complexity inherent in a multisubunit, multistate system. Here, we develop a stochastic particle-based model of CaMKII activation and dynamics that overcomes combinatorial complexity without significant approximations. We report four major findings. First, the CaMKII model system is never bistable at resting calcium concentrations, which suggests that CaMKII activity does not function as the biochemical switch underlying long-term memory. Second, the steady-state activation curves are either laserlike or steplike. Both are characterized by a well-defined threshold for activation, which suggests that thresholding is a robust feature of this system. Third, transiently activated CaMKII can maintain its activity over the time course of many experiments, and such slow deactivation may account for the few reports of bistability in the literature. And fourth, under in vivo conditions, increases in phosphatase activity can increase CaMKII activity. This is a surprising and counterintuitive effect, as dephosphorylation is generally associated with CaMKII deactivation. Copyright © 2013 Biophysical Society. Published by Elsevier Inc. All rights reserved.