Sample records for quahog arctica islandica

  1. Short and long-term effects of hydraulic dredging on benthic communities and ocean quahog (Arctica islandica) populations.

    PubMed

    Ragnarsson, Stefán Áki; Thorarinsdóttir, Gudrún G; Gunnarsson, Karl

    2015-08-01

    The short and long-term effects of hydraulic dredging on ocean quahog (Arctica islandica) populations and on non-target organisms were examined in Þistilfjörður Bay, NE Iceland over a five-year period. The overall species richness was low and the fauna was composed of species typical of sandy seabeds characterised by frequent wave-induced disturbances. The initial effects of dredging on the overall benthic community were large. Most taxa were significantly affected by dredging, with abundances sometimes decreasing or increasing by more than 50% immediately after dredging. However, with the exception of the ocean quahog, their recovery was rapid, and most taxa attained similar abundances as in the undisturbed control sediments after three months, and all did so after about a year. The effects of dredging on ocean quahogs were drastic and long-lasting. Of the original ocean quahog biomass before fishing took place, the dredge captured 82%, while a further 11% was lost as a result of mortality due to shell damage and predation. The total direct and indirect loss of ocean quahog biomass within dredged tracks due to fishing was thus 93%. The recovery of ocean quahogs in fished areas was extremely slow. Five years after dredging, the total ocean quahog biomass in tracks had increased from 7% to 26% relative to that in the controls. The proportional increase among ocean quahogs of targeted sizes (>70 mm) was from 2% to 14% over the same period. This study shows that while the longer-term effects of hydraulic dredging on non-target benthic organisms were small, the effects of dredging on ocean quahog densities were drastic, with full recovery expected to take place on decadal time-scales. The impacts of dredging on ocean quahog populations at the scale of the fishery are discussed. Copyright © 2015. Published by Elsevier Ltd.

  2. Experimental validation of environmental controls on the δ13C of Arctica islandica (ocean quahog) shell carbonate

    NASA Astrophysics Data System (ADS)

    Beirne, Erin C.; Wanamaker, Alan D.; Feindel, Scott C.

    2012-05-01

    The marine bivalve species, Arctica islandica, was reared under experimental conditions for 29 weeks in the Gulf of Maine in order to determine the relationship between the carbon isotope composition of shell carbonate (δ13CS) and ambient seawater dissolved inorganic carbon (δ13CDIC), as well as to approximate the metabolic contribution (CM) to shell material. Three experimental environments were compared: two flow-through tanks (one at ambient seawater conditions, one with a supplemental food source) and an in situ cage. Each environment contained 50 juveniles and 30 adults. Both juvenile (2-3 years) and adult (19-64 years) specimens displayed average percent CM of less than or equal to 10% when using three different proxies of respired carbon: digestive gland, adductor muscle and sediment. Hence, the primary control on δ13CS values is ambient DIC. The relationship between δ13CDIC and δ13CS for 114 individuals used in the study was: δ13C=δ13C-1.0‰(±0.3‰) No ontogenetic effect on δ13CS was observed, and growth rates did not generally impact δ13CS values. Based on the results of this study, shell material derived from the long-lived ocean quahog (A. islandica) constitutes a viable proxy for paleo-DIC from the extratropical Atlantic Ocean.

  3. Sr heterogeneity in textit{Arctica islandica} shells and the potential use of Sr/Ca ratios as paleotemperature proxies

    NASA Astrophysics Data System (ADS)

    Radermacher, Pascal; Schöne, Bernd R.; Nunn, Elizabeth V.; Zengjie, Zhang

    2010-05-01

    Quantifiable paleotemperature data can help to verify predictions made by numerical climate models. Traditionally, paleotemperature estimates are based on δ18O values of biogenic hard parts. However, oxygen isotope values not only reflect changes in ambient temperature, but also changes in δ18Owater, i.e. driven by freshwater influx, evaporation etc. Information regarding the δ18Owater value of past environments is limited for the geological past. The validity of published δ18O paleotemperature data can be tested using element-to-calcium ratios of bivalve shells such as the long-lived ocean quahog, Arctica islandica. Preliminary investigations suggest that Sr/Ca ratios of this species may provide more reliable paleotemperature data. However, contemporaneously deposited shell portions within the outer shell layer demonstrate at least a 30% variability in the Sr/Ca value. This study presents Sr/Ca ratios measured by ICP-OES wet-chemical analyses. Significantly different distributions of Sr/Ca ratios were recorded from the shell surface (over 1330 ppm), through the interior (850 ppm) and to the inner shell surface (1860 ppm). Furthermore, this study showed that different shell crystal fabrics incorporate different amounts of Sr into the CaCO3 lattice of the A. islandica shell. Disparate Sr distribution could potentially be explained either by postdepositional diagenetic processes or syndepositional processes during biomineralization (i.e. different amounts of Sr incorporated into the shell). Understanding the mechanism of the observed Sr heterogeneity is essential if Sr/Ca ratios are to be used confidently in paleotemperature reconstructions.

  4. LA-ICP-MS-derived U-concentrations and microstructural domains within biogenic aragonite of Arctica islandica shell.

    PubMed

    Helama, Samuli; Heikkilä, Pasi; Rinne, Katja; Nielsen, Jan Kresten; Nielsen, Jesper Kresten

    2015-05-01

    Understanding of the uranium uptake processes (both in vivo and post-mortem) into the skeletal structures of marine calcifiers is a subject of multi-disciplinary interest. U-concentration changes within the molluscan shell may serve as a paleoceanographic proxy of the pH history. A proxy of this type is needed to track the effects of fossil fuel emissions to ocean acidification. Moreover, attaining reliable U-series dates using shell materials would be a geochronological breakthrough. Picturing the high-resolution changes of U-concentrations in shell profiles is now possible by laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS). Here, we analyzed in situ U-concentration variations in sub-fossilized shells of ocean quahog (Arctica islandica), a commonly studied bivalve species in Quaternary geoscience, using LA-ICP-MS. Microstructural details of the shell profiles were achieved by the scanning electron microscopy (SEM). Comparison of the shell aragonite microstructure with the changes in U-concentration revealed that uranium of possibly secondary origin is concentrated into the porous granular layers of the shell. Our results reinforce the hypothesis that U-concentration variations can be linked with microstructural differences within the shell. A combination of LA-ICP-MS and SEM analyses is recommended as an interesting approach for understanding the U-concentration variations in similar materials.

  5. Comparisons of multiple isotope systems in the aragonitic shells of cultured Arctica islandica clams

    NASA Astrophysics Data System (ADS)

    Liu, Y. W.; Aciego, S.; Wanamaker, A. D.

    2014-12-01

    Previous work using oxygen and stable carbon isotopes from Arctica islandica shells has shown that this archive can provide information on past seawater temperatures, carbon cycling and ocean circulation. However, relatively less attention has been devoted to other "non-traditional" isotope systems within this proxy archive. In this study, we report the boron (δ11B) and strontium isotopic values (87Sr/86Sr and δ88/86Sr) from A. islandicashells collected and cultured from the Gulf of Maine. The long-lived ocean quahog, A. islandica was collected and cultured in the Gulf of Maine for 8 months. Our high-resolution δ11B records from the experiment show 5-7‰ of increase through the culture, with low values from January to May and higher values after May. The 87Sr/86Sr ratios from both tank water and shell samples suggest that the shell material reflects ambient ocean chemistry without interferences from terrestrial sources. Although It has been suggested that stable Sr isotopic ratios (δ88/86Sr) in biogenic carbonates are influenced by the temperature of the precipitating fluid, our nearly identical δ88/86Sr data do not support this hypothesis despite a 15 °C temperature change during the experiment. Based on the in-situ measurements of culture seawater temperature, salinity and pH, and two commonly used fractionation factors (α3-4) for corals and forams, we predicted the range in shell δ11B values for the experiment. Our boron results are at the extreme ends of the two prediction lines suggesting the potential usage of the bivalve shells as seawater pH indicator. However, the wider range in δ11B in this experiment than the predictions based on other carbonate organisms (only 2 to 3‰) suggests that a species-specific fractionation factor may be required. Recent work from an additional constant temperature experiment (10 and 15 °C) in the Gulf of Maine will allow us to further evaluate temperature influences and potential vital effects on the shell boron

  6. Growth of juvenile Arctica islandica under experimental conditions

    NASA Astrophysics Data System (ADS)

    Witbaard, R.; Franken, R.; Visser, B.

    1998-02-01

    In two laboratory experiments, the effects of temperature and food availability on the growth of 10- to 23-mm high specimens of the bivalve Arctica islandica were estimated. Each experimental set-up consisted of 5 treatments in which either the food supply or the temperature differed. It was demonstrated that Arctica is able to grow at temperatures as low as 1°C. A tenfold increase of shell growth was observed at temperatures between 1° and 12°C. The greatest change in growth rate took place between 1° and 6°C. Average instantaneous shell growth varies between 0.0003 at 1°C to 0.0032/day at 12°C. The results suggest that temperature hardly affects the time spent in filtration, whereas particle density strongly influences that response. Starved animals at 9°C have their siphons open during only 12% of the time, whereas the siphons of optimally fed animals were open on average during 76% of the observations. Increased siphon activity corresponded to high shell and tissue growth. At 9°C, average shell growth at the optimum cell density of 20×106 cell/l was 3.1 mm corresponding to an instantaneous rate of 0.0026/day. An algal cell density ( Isochrysis galbana, Dunaliella marina) ranging between 5 and 7×106 cell/l is just enough to keep shells alive at 9°C. Carbon conversion efficiency at 9°C is estimated to vary between 11 and 14%.

  7. A heart that beats for 500 years: age-related changes in cardiac proteasome activity, oxidative protein damage and expression of heat shock proteins, inflammatory factors, and mitochondrial complexes in Arctica islandica, the longest-living noncolonial animal.

    PubMed

    Sosnowska, Danuta; Richardson, Chris; Sonntag, William E; Csiszar, Anna; Ungvari, Zoltan; Ridgway, Iain

    2014-12-01

    Study of negligibly senescent animals may provide clues that lead to better understanding of the cardiac aging process. To elucidate mechanisms of successful cardiac aging, we investigated age-related changes in proteasome activity, oxidative protein damage and expression of heat shock proteins, inflammatory factors, and mitochondrial complexes in the heart of the ocean quahog Arctica islandica, the longest-lived noncolonial animal (maximum life span potential: 508 years). We found that in the heart of A. islandica the level of oxidatively damaged proteins did not change significantly up to 120 years of age. No significant aging-induced changes were observed in caspase-like and trypsin-like proteasome activity. Chymotrypsin-like proteasome activity showed a significant early-life decline, then it remained stable for up to 182 years. No significant relationship was observed between the extent of protein ubiquitination and age. In the heart of A. islandica, an early-life decline in expression of HSP90 and five mitochondrial electron transport chain complexes was observed. We found significant age-related increases in the expression of three cytokine-like mediators (interleukin-6, interleukin-1β, and tumor necrosis factor-α) in the heart of A. islandica. Collectively, in extremely long-lived molluscs, maintenance of protein homeostasis likely contributes to the preservation of cardiac function. Our data also support the concept that low-grade chronic inflammation in the cardiovascular system is a universal feature of the aging process, which is also manifest in invertebrates. © The Author 2013. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  8. Reconstructing coastal environmental condition in the eastern Norwegian Sea by means of Arctica islandica sclerochronological records

    NASA Astrophysics Data System (ADS)

    Trofimova, Tamara; Andersson, Carin

    2015-04-01

    Paleo archives are fundament in improving our knowledge of the natural climate variability. Established marine proxy records for the ocean, especially for high latitudes, are both sparsely distributed and are poorly resolved in time. The identification and development of new archives and proxies for studying key ocean processes at annual to sub-annual resolution that can extend the marine instrumental record is therefore a clear priority for marine climate science. The bivalve species Arctica islandica is a unique paleoclimatic archive with an exceptional longevity combined with high temporal resolution, due to accretion of annual growth increments. The aim of this study is to use sclerochronological records of A. islandica to extend instrumental hydrographic records and increase our understanding of a variability of a Norwegian Coastal Current (NCC). The NCC transports warm, low-salinity water northwards, which eventually plays role for the Arctic halocline. Moreover, previous investigations showed the connection of properties and variability of the NCC with catches of commercially valuable fishes. The knowledge of the variability of the NCC is also essential for possible future prediction climate conditions and fish stock variability in the region. In this study we use shells of Arctica islandica collected off the coast of Eggum (Lofoten, Norway). The material was obtained from the depth 5-10 m by dredging along the seabed and by means of scuba divers. We examine the growth patterns of living and subfossil shells. Ongoing work mainly focuses on the construction of a composite growth chronology based on increment-width time series. The results we will compare with existing time series of the environment and climatic parameters to determine the controlling factors and test the applicability of growth chronology in a climate reconstruction. Furthermore, we will perform geochemical analyses of the stable isotope composition (δ18O and δ13C) in shell carbonate to

  9. Interactive effects of temperature and food availability on the growth of Arctica islandica (Bivalvia) juveniles.

    PubMed

    Ballesta-Artero, Irene; Janssen, Reneé; van der Meer, Jaap; Witbaard, Rob

    2018-02-01

    The interest in Arctica islandica growth biology has recently increased due to the widespread use of its shell as a bioarchive. Although temperature and food availability are considered key factors in its growth, their combined influence has not been studied so far under laboratory conditions. We tested the interactive effect of temperature and food availability on the shell and tissue growth of A. islandica juveniles (9-15 mm in height) in a multi-factorial experiment with four food levels (no food, low, medium, and high) and three different temperatures (3, 8, 13 °C). Shell and tissue growth were observed in all treatments, with significant differences occurring only among food levels (2-way ANOVA; P-value < 0.05). Siphon activity (% open siphons), however, was affected by temperature, food, and the interaction between them (2-way ANOVA; P-value < 0.05). Siphon observations, as indication of feeding activities, played a key role to better understand the growth variation between individuals. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. The effects of environment on Arctica islandica shell formation and architecture

    NASA Astrophysics Data System (ADS)

    Milano, Stefania; Nehrke, Gernot; Wanamaker, Alan D., Jr.; Ballesta-Artero, Irene; Brey, Thomas; Schöne, Bernd R.

    2017-03-01

    Mollusks record valuable information in their hard parts that reflect ambient environmental conditions. For this reason, shells can serve as excellent archives to reconstruct past climate and environmental variability. However, animal physiology and biomineralization, which are often poorly understood, can make the decoding of environmental signals a challenging task. Many of the routinely used shell-based proxies are sensitive to multiple different environmental and physiological variables. Therefore, the identification and interpretation of individual environmental signals (e.g., water temperature) often is particularly difficult. Additional proxies not influenced by multiple environmental variables or animal physiology would be a great asset in the field of paleoclimatology. The aim of this study is to investigate the potential use of structural properties of Arctica islandica shells as an environmental proxy. A total of 11 specimens were analyzed to study if changes of the microstructural organization of this marine bivalve are related to environmental conditions. In order to limit the interference of multiple parameters, the samples were cultured under controlled conditions. Three specimens presented here were grown at two different water temperatures (10 and 15 °C) for multiple weeks and exposed only to ambient food conditions. An additional eight specimens were reared under three different dietary regimes. Shell material was analyzed with two techniques; (1) confocal Raman microscopy (CRM) was used to quantify changes of the orientation of microstructural units and pigment distribution, and (2) scanning electron microscopy (SEM) was used to detect changes in microstructural organization. Our results indicate that A. islandica microstructure is not sensitive to changes in the food source and, likely, shell pigment are not altered by diet. However, seawater temperature had a statistically significant effect on the orientation of the biomineral. Although

  11. Links between phytoplankton dynamics and shell growth of Arctica islandica on the Faroe Shelf

    NASA Astrophysics Data System (ADS)

    Bonitz, Fabian Georg Wulf; Andersson, Carin; Trofimova, Tamara; Hátún, Hjálmar

    2018-03-01

    The phytoplankton dynamics on the Faroe Shelf are strongly connected to higher trophic levels, and their inter-annual variability has great importance for many organisms, including the principal fish stocks. Hence, information on the marked phytoplankton variability is scientifically and economically valuable. We show here that the shell growth variability in Arctica islandica shells has the potential to identify periods of increased and decreased phytoplankton concentrations on the Faroe Shelf and in the wider Faroese region in previous centuries. The growth of A. islandica has often been linked to changes in phytoplankton concentrations, i.e., food availability. By cross-matching life-collected and sub-fossil A. islandica shells from two separate locations on the Faroe Shelf, we have built a master chronology, which reaches back to the 17th century. This master chronology correlates well with a Primary Production index for the Faroe Shelf (r = 0.65; p < 0.01) and average April-June chlorophyll a concentrations in the central part of the shelf (r = 0.74; p < 0.01). A link is also identified between the shell growth and phytoplankton concentrations over the wider Faroese Channel Region, as represented in the Continuous Plankton Recorder surveys, especially for the months June-September (r = 0.39; p < 0.01). In addition, an inverse relationship is observed between the master chronology and on-shelf water temperatures from June-September (r = - 0.29; p < 0.01), which is likely associated with a previously reported inverse relationship between temperatures and the on-shelf primary production. An analysis of the δ18O in the shells shows that the main growing season of the shells presumably occurs during the spring and summer months, which concurs with the main spring bloom.

  12. Connections between the growth of Arctica islandica and phytoplankton dynamics on the Faroe Shelf

    NASA Astrophysics Data System (ADS)

    Bonitz, Fabian; Andersson, Carin; Trofimova, Tamara

    2017-04-01

    In this study we use molluscan sclerochronological techniques in order to obtain closer insights into environmental and ecological dynamics of Faroe Shelf waters. The Faroe Shelf represents a special ecosystem with rich benthic and neritic communities, which also have great importance for many economically relevant fish stocks. Thus, a better understanding of seasonal and year-to-year phytoplankton and stratification dynamics would be useful because they also have implications for higher trophic levels. The water masses of the Faroe Shelf are fairly homogenous and isolated from off-shelf waters but at a certain depth, which is referred to as transition zone, seasonal stratification and horizontal exchange occur. Systematic observations and phytoplankton dynamic investigations have only been performed during the last 29 years but longer records are missing. Thus, we use the growth increment variability in long-lived Arctica islandica shells from the transition zone of the eastern Faroe Shelf to evaluate its potential to estimate on-shelf phytoplankton and stratification dynamics since previous studies have shown that the growth of A. islandica is highly dependent on food availability. We have built a shell-based master-chronology reaching back to the 17th century. Comparisons between the growth indices of our chronology and fluorescence data reveal significant positive relationships. In combination with an index that accounts for stratification even stronger correlations are obtained. This indicates that the growth of A. islandica is largely influenced by a combination of how much phytoplankton is produced and how much actually reaches the bottom, i.e. how well-mixed the water column is. Further significant positive correlations can also be found between the growth indices and other primary productivity data from the Faroe Shelf. In conclusion, our results suggest that the growth indices can be related to year-to-year changes in phytoplankton production and

  13. The death assemblage as a marker for habitat and an indicator of climate change: Georges Bank, surfclams and ocean quahogs

    NASA Astrophysics Data System (ADS)

    Powell, Eric N.; Kuykendall, Kelsey M.; Moreno, Paula

    2017-06-01

    A comprehensive dataset for the Georges Bank region is used to directly compare the distribution of the death assemblage and the living community at large spatial scales and to assess the application of the death assemblage in tracking changes in species' distributional pattern as a consequence of climate change. Focus is placed on the biomass-dominant clam species of the northwest Atlantic continental shelf: the surfclam Spisula solidissima and the ocean quahog Arctica islandica, for which extensive datasets exist on the distributions of the living population and the death assemblage. For both surfclams and ocean quahogs, the distribution of dead shells, in the main, tracked the distribution of live animals relatively closely. Thus, for both species, the presence of dead shells was a positive indicator of present, recent, or past occupation by live animals. Shell dispersion within habitat was greater for surfclams than for ocean quahogs either due to spatial time averaging, animals not living in all habitable areas all of the time, or parautochthonous redistribution of shell. The regional distribution of dead shell differed from the distribution of live animals, for both species, in a systematic way indicative of range shifts due to climate change. In each case the differential distribution was consistent with warming of the northwest Atlantic. Present-day overlap of live surfclams with live ocean quahogs was consistent with the expectation that the surfclam's range is shifting into deeper water in response to the recent warming trend. The presence of locations devoid of dead shells where live surfclams nevertheless were collected measures the recentness of this event. The presence of dead ocean quahog shells at shallower depths than live ocean quahogs offers good evidence that a range shift has occurred in the past, but prior to the initiation of routine surveys in 1980. Possibly, this range shift tracks initial colonization at the end of the Little Ice Age.

  14. Environmental controls on the boron and strontium isotopic composition of aragonite shell material of cultured Arctica islandica

    NASA Astrophysics Data System (ADS)

    Liu, Y.-W.; Aciego, S. M.; Wanamaker, A. D., Jr.

    2015-02-01

    Ocean acidification, the decrease in ocean pH associated with increasing atmospheric CO2, is likely to impact marine organisms, particularly those that produce carbonate skeletons or shells. Therefore it is important to investigate how environmental factors (seawater pH, temperature and salinity) influence the chemical compositions in biogenic carbonates. In this study we report the first high-resolution strontium (87Sr / 86Sr and δ88 / 86Sr) and boron (δ11B) isotopic values in the aragonite shell of cultured Arctica islandica (A. islandica). The 87Sr / 86Sr ratios from both tank water and shell samples show ratios nearly identical to the open ocean, which suggests that the shell material reflects ambient ocean chemistry without terrestrial influence. The 84Sr-87Sr double spike resolved shell δ 88 / 86Sr and Sr concentration data show no resolvable change throughout the culture period and reflect no theoretical kinetic mass fractionation throughout the experiment despite a temperature change of more than 15 °C. The δ11B records from the experiment show at least a 5‰ increase through the culture season (January 2010-August 2010), with low values from beginning to week 19 and higher values hereafter. The larger range in δ11B in this experiment compared to predictions based on other carbonate organisms (2-3‰) suggests that a species-specific fractionation factor may be required. A relatively strong correlation between the Δ pH (pHshell-pHsw) and seawater pH (pHsw) was observed (R2 = 0.34), which suggests that A. islandica partly regulates the pH of the extrapallial fluid. However, this proposed mechanism only explains approximately 34% of the variance in the δ11B data. Instead, a rapid rise in δ11B after week 19 suggests that the boron uptake of the shell changes when a temperature threshold of 13 °C is reached.

  15. Environmental controls on the boron and strontium isotopic composition of aragonite shell material of cultured Arctica islandica

    NASA Astrophysics Data System (ADS)

    Liu, Y.-W.; Aciego, S. M.; Wanamaker, A. D., Jr.

    2015-06-01

    Ocean acidification, the decrease in ocean pH associated with increasing atmospheric CO2, is likely to impact marine organisms, particularly those that produce carbonate skeletons or shells. Therefore, it is important to investigate how environmental factors (seawater pH, temperature and salinity) influence the chemical compositions in biogenic carbonates. In this study we report the first high-resolution strontium (87Sr / 86Sr and δ88 / 86Sr) and boron (δ11B) isotopic values in the aragonite shell of cultured Arctica islandica (A. islandica). The 87Sr / 86Sr ratios from both tank water and shell samples show ratios nearly identical to the open ocean, which suggests that the shell material reflects ambient ocean chemistry without terrestrial influence. The 84Sr-87Sr double-spike-resolved shell δ88 / 86Sr and Sr concentration data show no resolvable change throughout the culture period and reflect no theoretical kinetic mass fractionation throughout the experiment despite a temperature change of more than 15 °C. The δ11B records from the experiment show at least a 5‰ increase through the 29-week culture season (January 2010-August 2010), with low values from the beginning to week 19 and higher values thereafter. The larger range in δ11B in this experiment compared to predictions based on other carbonate organisms (2-3‰) suggests that a species-specific fractionation factor may be required. A significant correlation between the ΔpH (pHshell - pHsw) and seawater pH (pHsw) was observed (R2 = 0.35), where the pHshell is the calcification pH of the shell calculated from boron isotopic composition. This negative correlation suggests that A. islandica partly regulates the pH of the extrapallial fluid. However, this proposed mechanism only explains approximately 35% of the variance in the δ11B data. Instead, a rapid rise in δ11B of the shell material after week 19, during the summer, suggests that the boron uptake changes when a thermal threshold of > 13 °C is

  16. Behavioral responses of Arctica islandica (Bivalvia: Arcticidae) to simulated leakages of carbon dioxide from sub-sea geological storage.

    PubMed

    Bamber, Shaw D; Westerlund, Stig

    2016-11-01

    Sub-sea geological storage of carbon dioxide (CO 2 ) provides a viable option for the Carbon Capture and Storage (CCS) approach for reducing atmospheric emissions of this greenhouse gas. Although generally considered to offer a low risk of major leakage, it remains relevant to establish the possible consequences for marine organisms that live in or on sediments overlying these storage areas if such an event may occur. The present study has used a series of laboratory exposures and behavioral bioassays to establish the sensitivity of Arctica islandica to simulated leakages of CO 2 . This long-lived bivalve mollusc is widely distributed throughout the North Sea, an area where geological storage is currently taking place and where there are plans to expand this operation significantly. A recently published model has predicted a maximum drop of 1.9pH units in seawater at the point source of a substantial escape of CO 2 from sub-sea geological storage in this region. Valve movements of A. islandica exposed to reduced pH seawater were recorded continuously using Hall effect proximity sensors. Valve movement regulation is important for optimising the flow of water over the gills, which supplies food and facilitates respiration. A stepwise reduction in seawater pH showed an initial increase in both the rate and extent of valve movements in the majority of individuals tested when pH fell to 6.2 units. Exposing A. islandica to pH 6.2 seawater continuously for seven days resulted in a clear increase in valve movements during the first 40h of exposure, followed by a gradual reduction in activity intensity over the subsequent five days, suggesting acclimation. The ability of both exposed and control bivalves to burrow successfully into sediment on completion of this exposure was very similar. A final exposure trial, testing whether increased valve movements initiated by reduced pH were related to foot extension during attempted burrowing, found no such association. In summary

  17. Seasonality of bottom water temperature in the northern North Sea reconstructed from the oxygen isotope composition of the bivalve Arctica islandica

    NASA Astrophysics Data System (ADS)

    Trofimova, Tamara; Andersson, Carin; Bonitz, Fabian

    2017-04-01

    The seasonality of temperature changes is an important characteristic of climate. However, observational data for the ocean are only available for the last 150 year from a limited number of locations. Prior to 18th century information is only available from proxy reconstructions. The vast majority of such reconstructions depend on land-based archives, primarily from dendrochronology. Established marine proxy records for the ocean, especially at high latitudes, are both sparsely distributed and poorly resolved in time. Therefore, the identification and development of proxies for studying key ocean processes at sub-annual resolution that can extend the marine instrumental record is a clear priority in marine climate science. In this study, we have developed a record of early Holocene seasonal variability of bottom water temperature from the Viking Bank in the northern most North Sea. This area is of a particular interest since the hydrography is controlled by the inflow of Atlantic water. The reconstruction is based on the oxygen isotope composition of the growth increments in two sub-fossil shells of Arctica islandica (Bivalvia), dated to 9600-9335 cal. yr BP. By combining radiocarbon dating and sclerochronological techniques a floating chronology spanning over 200 years was constructed. Using the chronology as an age model, oxygen isotope measurements from 2 shells were combined into a 22-years long record. The results from this oxygen isotope record are compared with stable oxygen isotope profiles from modern shells to estimate changes in the mean state and seasonality between present and early Holocene. Shell-derived oxygen isotope values together with ice-volume corrected oxygen isotope values for the seawater were used to calculate bottom-water temperatures on a sub-annual time-scale. Preliminary results of the reconstructed early Holocene bottom water temperature indicate higher seasonality and lower minimum temperature compared to the present.

  18. A multi-centennial time series of well-constrained ΔR values for the Irish Sea derived using absolutely-dated shell samples from the mollusc Arctica islandica

    NASA Astrophysics Data System (ADS)

    Butler, P. G.; Scourse, J. D.; Richardson, C. A.; Wanamaker, A. D., Jr.

    2009-04-01

    Determinations of the local correction (ΔR) to the globally averaged marine radiocarbon reservoir age are often isolated in space and time, derived from heterogeneous sources and constrained by significant uncertainties. Although time series of ΔR at single sites can be obtained from sediment cores, these are subject to multiple uncertainties related to sedimentation rates, bioturbation and interspecific variations in the source of radiocarbon in the analysed samples. Coral records provide better resolution, but these are available only for tropical locations. It is shown here that it is possible to use the shell of the long-lived bivalve mollusc Arctica islandica as a source of high resolution time series of absolutely-dated marine radiocarbon determinations for the shelf seas surrounding the North Atlantic ocean. Annual growth increments in the shell can be crossdated and chronologies can be constructed in a precise analogue with the use of tree-rings. Because the calendar dates of the samples are known, ΔR can be determined with high precision and accuracy and because all the samples are from the same species, the time series of ΔR values possesses a high degree of internal consistency. Presented here is a multi-centennial (AD 1593 - AD 1933) time series of 31 ΔR values for a site in the Irish Sea close to the Isle of Man. The mean value of ΔR (-62 14C yrs) does not change significantly during this period but increased variability is apparent before AD 1750.

  19. 50 CFR 648.76 - Maine mahogany quahog zone.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Atlantic Surf Clam and Ocean Quahog Fisheries § 648.76 Maine mahogany quahog zone. (a) Landing requirements... Advisory Panel shall make recommendations, through the Surf Clam and Ocean Quahog Committee of the Council...

  20. 50 CFR 648.72 - Surfclam and ocean quahog specifications.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 12 2014-10-01 2014-10-01 false Surfclam and ocean quahog specifications... Measures for the Atlantic Surf Clam and Ocean Quahog Fisheries § 648.72 Surfclam and ocean quahog specifications. (a) Establishing catch quotas. The amount of surfclams or ocean quahogs that may be caught...

  1. 50 CFR 648.72 - Surfclam and ocean quahog specifications.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 50 Wildlife and Fisheries 12 2012-10-01 2012-10-01 false Surfclam and ocean quahog specifications... Measures for the Atlantic Surf Clam and Ocean Quahog Fisheries § 648.72 Surfclam and ocean quahog specifications. (a) Establishing catch quotas. The amount of surfclams or ocean quahogs that may be caught...

  2. 50 CFR 648.72 - Surfclam and ocean quahog specifications.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 12 2013-10-01 2013-10-01 false Surfclam and ocean quahog specifications... Measures for the Atlantic Surf Clam and Ocean Quahog Fisheries § 648.72 Surfclam and ocean quahog specifications. (a) Establishing catch quotas. The amount of surfclams or ocean quahogs that may be caught...

  3. Experimental diagenesis: insights into aragonite to calcite transformation of Arctica islandica shells by hydrothermal treatment

    NASA Astrophysics Data System (ADS)

    Casella, Laura A.; Griesshaber, Erika; Yin, Xiaofei; Ziegler, Andreas; Mavromatis, Vasileios; Müller, Dirk; Ritter, Ann-Christine; Hippler, Dorothee; Harper, Elizabeth M.; Dietzel, Martin; Immenhauser, Adrian; Schöne, Bernd R.; Angiolini, Lucia; Schmahl, Wolfgang W.

    2017-03-01

    Biomineralised hard parts form the most important physical fossil record of past environmental conditions. However, living organisms are not in thermodynamic equilibrium with their environment and create local chemical compartments within their bodies where physiologic processes such as biomineralisation take place. In generating their mineralised hard parts, most marine invertebrates produce metastable aragonite rather than the stable polymorph of CaCO3, calcite. After death of the organism the physiological conditions, which were present during biomineralisation, are not sustained any further and the system moves toward inorganic equilibrium with the surrounding inorganic geological system. Thus, during diagenesis the original biogenic structure of aragonitic tissue disappears and is replaced by inorganic structural features. In order to understand the diagenetic replacement of biogenic aragonite to non-biogenic calcite, we subjected Arctica islandica mollusc shells to hydrothermal alteration experiments. Experimental conditions were between 100 and 175 °C, with the main focus on 100 and 175 °C, reaction durations between 1 and 84 days, and alteration fluids simulating meteoric and burial waters, respectively. Detailed microstructural and geochemical data were collected for samples altered at 100 °C (and at 0.1 MPa pressure) for 28 days and for samples altered at 175 °C (and at 0.9 MPa pressure) for 7 and 84 days. During hydrothermal alteration at 100 °C for 28 days most but not the entire biopolymer matrix was destroyed, while shell aragonite and its characteristic microstructure was largely preserved. In all experiments up to 174 °C, there are no signs of a replacement reaction of shell aragonite to calcite in X-ray diffraction bulk analysis. At 175 °C the replacement reaction started after a dormant time of 4 days, and the original shell microstructure was almost completely overprinted by the aragonite to calcite replacement reaction after 10 days

  4. 50 CFR 648.76 - Maine mahogany quahog zone.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Measures for the Atlantic Surf Clam and Ocean Quahog Fisheries § 648.76 Maine mahogany quahog zone. Link to... northward toward Atlantic Beach Light in New York to the limit of the state territorial waters of New York... south of 42°20′ N. lat. (b) Areas closed because of small surfclams. Areas may be closed because they...

  5. 50 CFR 648.73 - Surfclam and ocean quahog Accountability Measures.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Accountability Measures. (a) Commercial ITQ fishery. (1) If the ACL for surfclam or ocean quahog is exceeded, and... an ACL overage that cannot be otherwise attributed to an ITQ allocation holder will be deducted from the appropriate ACL in the following fishing year. (b) Maine mahogany quahog fishery. If the ocean...

  6. 50 CFR 648.73 - Surfclam and ocean quahog Accountability Measures.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Accountability Measures. (a) Commercial ITQ fishery. (1) If the ACL for surfclam or ocean quahog is exceeded, and... an ACL overage that cannot be otherwise attributed to an ITQ allocation holder will be deducted from the appropriate ACL in the following fishing year. (b) Maine mahogany quahog fishery. If the ocean...

  7. 50 CFR 648.73 - Surfclam and ocean quahog Accountability Measures.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Accountability Measures. (a) Commercial ITQ fishery. (1) If the ACL for surfclam or ocean quahog is exceeded, and... an ACL overage that cannot be otherwise attributed to an ITQ allocation holder will be deducted from the appropriate ACL in the following fishing year. (b) Maine mahogany quahog fishery. If the ocean...

  8. Margolisiella islandica sp. nov. (Apicomplexa: Eimeridae) infecting Iceland scallop Chlamys islandica (Müller, 1776) in Icelandic waters.

    PubMed

    Kristmundsson, Árni; Helgason, Sigurður; Bambir, Slavko H; Eydal, Matthías; Freeman, Mark A

    2011-11-01

    Wild Iceland scallops Chlamys islandica from an Icelandic bay were examined for parasites. Queen scallops Aequipecten opercularis from the Faroe Islands and king scallops Pecten maximus and queen scallops from Scottish waters were also examined. Observations revealed heavy infections of eimeriorine parasites in 95-100% of C. islandica but not the other scallop species. All life stages in the apicomplexan reproduction phases, i.e. merogony, gametogony and sporogony, were present. Trophozoites and meronts were common within endothelial cells of the heart's auricle and two generations of free merozoites were frequently seen in great numbers in the haemolymph. Gamonts at various developmental stages were also abundant, most frequently free in the haemolymph. Macrogamonts were much more numerous than microgamonts. Oocysts were exclusively in the haemolymph; live mature oocysts contained numerous (>500) densely packed pairs of sporozoites forming sporocysts. Analysis of the 18S ribosomal DNA revealed that the parasite from C. islandica is most similar (97.7% identity) to an unidentified apicomplexan isolated from the haemolymph of the giant clam, Tridacna crocea, from Japan. Phylogenetic analyses showed that the novel sequence consistently grouped with the Tridacna sequence which formed a robust sister clade to the rhytidocystid group. We propose the name Margolisiella islandica sp. nov., referring to both type host and type locality. Copyright © 2011 Elsevier Inc. All rights reserved.

  9. 50 CFR 648.70 - Surfclam and ocean quahog Annual Catch Limit (ACL).

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Limit (ACL). 648.70 Section 648.70 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL... Annual Catch Limit (ACL). (a) The MAFMC staff shall recommend to the MAFMC ACLs for the surfclam and... Surfclam and Ocean Quahog FMP. The ACL for ocean quahog will then be allocated to the Maine and non-Maine...

  10. 50 CFR 648.70 - Surfclam and ocean quahog Annual Catch Limit (ACL).

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Limit (ACL). 648.70 Section 648.70 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL... Annual Catch Limit (ACL). (a) The MAFMC staff shall recommend to the MAFMC ACLs for the surfclam and... Surfclam and Ocean Quahog FMP. The ACL for ocean quahog will then be allocated to the Maine and non-Maine...

  11. 50 CFR 648.70 - Surfclam and ocean quahog Annual Catch Limit (ACL).

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Limit (ACL). 648.70 Section 648.70 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL... Annual Catch Limit (ACL). (a) The MAFMC staff shall recommend to the MAFMC ACLs for the surfclam and... Surfclam and Ocean Quahog FMP. The ACL for ocean quahog will then be allocated to the Maine and non-Maine...

  12. 50 CFR 648.79 - Surfclam and ocean quahog framework adjustments to management measures.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Surfclam and ocean quahog framework adjustments to management measures. (a) Within season management action... the FMP instead of a framework adjustment. (2) MAFMC recommendation. After developing management... 50 Wildlife and Fisheries 12 2012-10-01 2012-10-01 false Surfclam and ocean quahog framework...

  13. 50 CFR 648.79 - Surfclam and ocean quahog framework adjustments to management measures.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Surfclam and ocean quahog framework adjustments to management measures. (a) Within season management action... the FMP instead of a framework adjustment. (2) MAFMC recommendation. After developing management... 50 Wildlife and Fisheries 12 2013-10-01 2013-10-01 false Surfclam and ocean quahog framework...

  14. 50 CFR 648.79 - Surfclam and ocean quahog framework adjustments to management measures.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Surfclam and ocean quahog framework adjustments to management measures. (a) Within season management action... the FMP instead of a framework adjustment. (2) MAFMC recommendation. After developing management... 50 Wildlife and Fisheries 12 2014-10-01 2014-10-01 false Surfclam and ocean quahog framework...

  15. 50 CFR 648.79 - Surfclam and ocean quahog framework adjustments to management measures.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Surfclam and ocean quahog framework adjustments to management measures. (a) Within season management action... 50 Wildlife and Fisheries 10 2011-10-01 2011-10-01 false Surfclam and ocean quahog framework adjustments to management measures. 648.79 Section 648.79 Wildlife and Fisheries FISHERY CONSERVATION AND...

  16. A new notodelphyid copepod, Doropygopsis arctica sp. nov. (Cyclopoida), parasitic in ascidian of the Molgula arctica from the White Sea

    NASA Astrophysics Data System (ADS)

    Marchenkov, A. V.

    1998-06-01

    Doropygopsis arctica, a new species of notodelphyid cyclopoid from the branchial cavity of Molgula arctica Kiaer, 1896 (Ascidiacea) in Chupa Bay (Kandalakshskiy Zaliv, White Sea) is described. The new species differs from the two other congeners by the fine structure of some cephalosomic appendages and swimming legs. The diagnosis for Doropygopsis is redefined.

  17. 77 FR 72762 - Atlantic Surfclam and Ocean Quahog Fisheries; 2013 Fishing Quotas for Atlantic Surfclams and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-06

    ... Management Specialist, (978) 281-9177; fax (978) 281-9135. SUPPLEMENTARY INFORMATION: Section 648.72(c) of... (181 million L) for Atlantic surfclams, 5.333 million bu (284 million L) for ocean quahogs, and 100,000 Maine bu (3.524 million L) for Maine ocean quahogs, as announced in the Federal Register on December 27...

  18. Potential and limitation of combining terrestrial and marine growth records from Iceland

    NASA Astrophysics Data System (ADS)

    Piermattei, A.; Urbinati, C.; Tonelli, E.; Eggertsson, Ó.; Levanič, T.; Kaczka, R. J.; Andrew, C.; Schöne, B. R.; Büntgen, U.

    2017-08-01

    Seasonally formed, perennial growth increments of various organisms may possibly contain information about past environmental changes, well before instrumental measurements occurred. Such annually resolved proxy records have been mainly obtained from terrestrial archives, with a paucity of similar data originating from marine habitats. Iceland represents ideal conditions to develop both, tree ring (dendro) and bivalve shell (sclero) chronologies from adjacent sites. Here we introduce the first network of Icelandic birch (Betula pubescens Ehrh.) and rowan (Sorbus aucuparia) dendrochronologies, as well as ocean quahog (Arctica islandica L.) sclerochronologies. In order to identify the dominant external drivers of tree and shell growth, we assess the common growth trends and growth extremes within and between the terrestrial and marine records, as well as relationships of both archives with instrumental-based meteorological indices. Capturing a strong signal of June-August mean air temperature, the dendrochronologies are significantly positively correlated to each other. The sclerochronologies, however, reveal much lower growth coherency, which likely results from different sampling strategies and growth habitats. Disagreement between the dendro- and sclerochronologies possibly originates from unequal sample size, offset in the seasonal timing and rate of the growth, as well as varying sensitivities to different environmental factors. Our results emphasize the importance of considering a wide range of species and taxa to reconstruct a more complete picture of terrestrial and marine ecosystem functioning and productivity across various spatiotemporal scales.

  19. 50 CFR 648.71 - Surfclam and ocean quahog Annual Catch Targets (ACT).

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... and the sum of the Maine and non-Maine ocean quahog ACTs shall be less than or equal to the ACL for... of fishery performance relative to ACTs in conjunction with any ACL performance review, as outlined...

  20. 50 CFR 648.71 - Surfclam and ocean quahog Annual Catch Targets (ACT).

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... and the sum of the Maine and non-Maine ocean quahog ACTs shall be less than or equal to the ACL for... of fishery performance relative to ACTs in conjunction with any ACL performance review, as outlined...

  1. 50 CFR 648.71 - Surfclam and ocean quahog Annual Catch Targets (ACT).

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... and the sum of the Maine and non-Maine ocean quahog ACTs shall be less than or equal to the ACL for... of fishery performance relative to ACTs in conjunction with any ACL performance review, as outlined...

  2. 75 FR 20980 - Proposed Information Collection; Comment Request; Atlantic Surfclam and Ocean Quahog Framework...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-22

    ..., evaluate, and enforce fishery regulations. Framework Adjustment 1 (FW1) to the Atlantic Surf Clam and Ocean... DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration Proposed Information Collection; Comment Request; Atlantic Surfclam and Ocean Quahog Framework Adjustment I AGENCY: National...

  3. 75 FR 19356 - Proposed Information Collection; Comment Request; Atlantic Surfclam and Ocean Quahog Framework...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-14

    ..., evaluate, and enforce fishery regulations. Framework Adjustment 1 (FW1) to the Atlantic Surf Clam and Ocean... DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration Proposed Information Collection; Comment Request; Atlantic Surfclam and Ocean Quahog Framework Adjustment I AGENCY: National...

  4. Hydrographical variability and major ecosystem changes as recorded in the growth of Arctica islandica from the northern North Sea

    NASA Astrophysics Data System (ADS)

    Trofimova, Tamara; Andersson, Carin; Bonitz, Fabian

    2017-04-01

    Reconstruction of marine climate variability on regional to global scales requires a network of climatically sensitive annually resolved archives from key oceanographic locations. The small number of records existing to date impedes the application of a network approach. In this study, we aim at improving the spatial coverage of annually resolved paleo proxy records by investigating the impact of climate variability on sclerochronological records of A. islandica from the Viking Bank in the northern North Sea. The northern North Sea has an excellent oceanographic setting because its hydrography is primarily controlled by the major Atlantic water inflow to the North Sea. Using annual growth increment measurements of 30 shells we constructed a 265-year shell-growth chronology spanning the time interval AD 1748-2013. Chronology statistics (Rbar (>0.5) and EPS (>0.85)) indicate a robust signal of a common environmental forcing controlling shell growth for the major part of the record. Comparison with other sclerochronologies from the oceanographically related locations reveals a coherency on longer time scales, which is likely a response to a common environmental driver or a combination of such drivers. No significant correlation on the year-on-year level has been found between the chronology and time series of temperature and salinity from the area close to the study site. However, the timing of major hydrographical anomalies described for the region (Great Salinity Anomalies) coincide with a decrease in shell growth; likely in response to an impact on lower trophic levels, i.e. plankton composition and abundance. Spectral analysis of the chronology reveals a 21-26 year periodicity recorded in the shell growth. The variability on a similar time scale has been observed in multiple records from the North Atlantic and in model outputs. It has been suggested to represent one of the dominant scales of multi-decadal variability especially pronounced prior to the 20th century

  5. 76 FR 56322 - Atlantic Surfclam and Ocean Quahog Fisheries; 2012 Fishing Quotas for Atlantic Surfclams and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-13

    .... 101013504-0610-02] RIN 0648-XA529 Atlantic Surfclam and Ocean Quahog Fisheries; 2012 Fishing Quotas for.... ACTION: Temporary rule. SUMMARY: NMFS suspends the minimum size limit for Atlantic surfclams for the 2012... 2012 will remain status quo. Regulations governing these fisheries require NMFS to notify the public in...

  6. Sarcocystis arctica (Apicomplexa: Sarcocystidae): ultrastructural description and its new host record, the Alaskan wolf (Canis lupus).

    PubMed

    Calero-Bernal, Rafael; Cerqueira-Cézar, Camila K; Verma, Shiv Kumar; Mowery, Joseph; Carmena, David; Beckmen, Kimberlee; Dubey, Jitender P

    2016-07-01

    Sarcocystis sarcocysts are common in muscles of herbivores but are rare in muscles of carnivores. Here, we report sarcocysts in the muscles of a gray wolf (Canis lupus) from Alaska, USA, for the first time. Sarcocysts extracted from the tongue of the wolf were up to 900 μm long and slender and appeared to have a relatively thin wall by light microscope. By transmission electron microscopy, the sarcocyst wall most closely resembled "type 9c," and had a wavy parasitophorous vacuolar membrane folded as pleomorphic villar protrusions (vp), with anastomoses of tips. The vp and the ground substance (gs) layer were smooth without tubules or granules. The gs was up to 2.0 μm thick. The total width of the wall including vp and the gs was 3.5 μm. The vp were up to 1.5 μm long. Mature sarcocysts contained numerous bradyzoites and few metrocytes. The bradyzoites were 9.5 μm long and 1.5 μm wide, and contained all organelles found in Sarcocystis bradyzoites with at least two rhoptries. Molecular characterization showed the highest identity for 18S rRNA, 28S rRNA, ITS-1, and cox1 sequences of Sarcocystis arctica of the Arctic fox (Vulpes lagopus) from Norway. The ultrastructure of S. arctica from the fox is unknown. Here, we provide ultrastructure of S. arctica from the Alaskan wolf for the first time. The definitive host of S. arctica remains unknown.

  7. Are the Antarctic dipteran, Eretmoptera murphyi, and Arctic collembolan, Megaphorura arctica, vulnerable to rising temperatures?

    PubMed

    Everatt, M J; Convey, P; Worland, M R; Bale, J S; Hayward, S A L

    2014-08-01

    Polar terrestrial invertebrates are suggested as being vulnerable to temperature change relative to lower latitude species, and hence possibly also to climate warming. Previous studies have shown Antarctic and Arctic Collembola and Acari to possess good heat tolerance and survive temperature exposures above 30 °C. To test this feature further, the heat tolerance and physiological plasticity of heat stress were explored in the Arctic collembolan, Megaphorura arctica, from Svalbard and the Antarctic midge, Eretmoptera murphyi, from Signy Island. The data obtained demonstrate considerable heat tolerance in both species, with upper lethal temperatures ≥35 °C (1 h exposures), and tolerance of exposure to 10 and 15 °C exceeding 56 days. This tolerance is far beyond that required in their current environment. Average microhabitat temperatures in August 2011 ranged between 5.1 and 8.1 °C, and rarely rose above 10 °C, in Ny-Ålesund, Svalbard. Summer soil microhabitat temperatures on Signy Island have previously been shown to range between 0 and 10 °C. There was also evidence to suggest that E. murphyi can recover from high-temperature exposure and that M. arctica is capable of rapid heat hardening. M. arctica and E. murphyi therefore have the physiological capacity to tolerate current environmental conditions, as well as future warming. If the features they express are characteristically more general, such polar terrestrial invertebrates will likely fare well under climate warming scenarios.

  8. Identification and genetic characterization of Sarcocystis arctica and Sarcocystis lutrae in red foxes (Vulpes vulpes) from Baltic States and Spain.

    PubMed

    Kirillova, Viktorija; Prakas, Petras; Calero-Bernal, Rafael; Gavarāne, Inese; Fernández-García, José Luis; Martínez-González, Manuel; Rudaitytė-Lukošienė, Eglė; Martínez-Estéllez, Miguel Ángel Habela; Butkauskas, Dalius; Kirjušina, Muza

    2018-03-12

    Typically, carnivores serve as definitive hosts for Sarcocystis spp. parasites; currently, their role as intermediate hosts is being elucidated. The present study aimed to identify and molecularly characterize Sarcocystis cysts detected in striated muscle of red foxes from different populations in Latvia, Lithuania and Spain. Muscle samples from 411 red foxes (Vulpes vulpes) and 269 racoon dogs (Nyctereutes procyonoides) from Latvia, 41 red foxes from Lithuania and 22 red foxes from Spain were examined for the presence of Sarcocystis sarcocysts by light microscopy (LM). Sarcocystis spp. were identified by transmission electron microscopy (TEM) and molecular biology techniques. Sarcocystis cysts were detected in 11/411 (2.7%) Latvian, 3/41 (7.3%) Lithuanian, and 6/22 (27.3%) Spanish red foxes, however, cysts were not observed in the muscles of racoon dogs. Based on LM, TEM, 18S rDNA, 28S rDNA, ITS1, cox1 and rpoB sequences, Sarcocystis arctica and Sarcocystis lutrae cysts were identified in red fox muscles from Latvia and Lithuania, whereas only S. arctica was detected in Spain. The 18S rDNA, 28S rDNA and ITS1 sequences from the 21 isolates of S. arctica from Latvia, Lithuania and Spain were identical. By contrast, two and four haplotypes were determined based on mtDNA cox1 and apicoplast rpoB sequences, respectively. Polymorphisms were not detected between the two isolates of S. lutrae from Latvia and Lithuania. Based on phylogenetic results, S. arctica and S. lutrae were most closely related to Sarcocystis spp. using predatory mammals as intermediate hosts and to Sarcocystis species with a bird-bird life-cycle. Based on current knowledge, the red fox and Arctic fox (Vulpes lagopus) could act as intermediate host for the same two Sarcocystis species. Molecular results suggest the existence of two genetic lineages of S. arctica, and such divergence relies on its geographical distribution but not on their intermediate host species.

  9. Surviving the cold: molecular analyses of insect cryoprotective dehydration in the Arctic springtail Megaphorura arctica (Tullberg)

    PubMed Central

    Clark, Melody S; Thorne, Michael AS; Purać, Jelena; Burns, Gavin; Hillyard, Guy; Popović, Željko D; Grubor-Lajšić, Gordana; Worland, M Roger

    2009-01-01

    Background Insects provide tractable models for enhancing our understanding of the physiological and cellular processes that enable survival at extreme low temperatures. They possess three main strategies to survive the cold: freeze tolerance, freeze avoidance or cryoprotective dehydration, of which the latter method is exploited by our model species, the Arctic springtail Megaphorura arctica, formerly Onychiurus arcticus (Tullberg 1876). The physiological mechanisms underlying cryoprotective dehydration have been well characterised in M. arctica and to date this process has been described in only a few other species: the Antarctic nematode Panagrolaimus davidi, an enchytraied worm, the larvae of the Antarctic midge Belgica antarctica and the cocoons of the earthworm Dendrobaena octaedra. There are no in-depth molecular studies on the underlying cold survival mechanisms in any species. Results A cDNA microarray was generated using 6,912 M. arctica clones printed in duplicate. Analysis of clones up-regulated during dehydration procedures (using both cold- and salt-induced dehydration) has identified a number of significant cellular processes, namely the production and mobilisation of trehalose, protection of cellular systems via small heat shock proteins and tissue/cellular remodelling during the dehydration process. Energy production, initiation of protein translation and cell division, plus potential tissue repair processes dominate genes identified during recovery. Heat map analysis identified a duplication of the trehalose-6-phosphate synthase (TPS) gene in M. arctica and also 53 clones co-regulated with TPS, including a number of membrane associated and cell signalling proteins. Q-PCR on selected candidate genes has also contributed to our understanding with glutathione-S-transferase identified as the major antioxdidant enzyme protecting the cells during these stressful procedures, and a number of protein kinase signalling molecules involved in recovery

  10. The ESR age of Portlandia arctica shells from glacial deposits of Central Latvia . an answer to a controversy on the age and genesis of their enclosing sediments

    NASA Astrophysics Data System (ADS)

    Molodkov, Anatoly; Dreimanis, Aleksis; ĀBoltiņš, Ojars; Raukas, Anto

    The occurrence of Portlandia arctica shells in glacigenic sediments of Central Latvia had created a controversy in many publications about (1) their age ranging from the Holsteinian to the Late Weichselian and (2) the genesis of their enclosing sediments: glacial, glaciomarine or marine. Our reinvestigation of the main object of controversy, the Lı¯čupe site, leads to a conclusion that the sedimentary package of diamictons, clays and sands containing Portlandia arctica shells and marine microfossils is a large glacial raft that had been transported and deposited by the Riga lobe during the Weichselian. The electron spin resonance (ESR) ages on five sets of Portlandia arctica shells from the Lı¯čupe and Daugmales Tomēni sites range from 86.0±6.8 to 105.0±9.2 ka BP. These ESR age determinations and the cool climate indicators of the associated microflora and microfauna suggest that their source sediments, probably in the Gulf of Riga, are marine clays of Early Weichselian age, probably correlative to the Brørup Interstadial. In Central Latvia Portlandia arctica shells and their enclosing clay occur resedimented or translocated in glacial deposits during Weichselian glacial advances.

  11. Decoupling of Nuclear Division Cycles and Cell Size during the Coenocytic Growth of the Ichthyosporean Sphaeroforma arctica.

    PubMed

    Ondracka, Andrej; Dudin, Omaya; Ruiz-Trillo, Iñaki

    2018-06-18

    Coordination of the cell division cycle with the growth of the cell is critical to achieve cell size homeostasis [1]. Mechanisms coupling the cell division cycle with cell growth have been described across diverse eukaryotic taxa [2-4], but little is known about how these processes are coordinated in organisms that undergo more complex life cycles, such as coenocytic growth. Coenocytes (multinucleate cells formed by sequential nuclear divisions without cytokinesis) are commonly found across the eukaryotic kingdom, including in animal and plant tissues and several lineages of unicellular eukaryotes [5]. Among the organisms that form coenocytes are ichthyosporeans, a lineage of unicellular holozoans that are of significant interest due to their phylogenetic placement as one of the closest relatives of animals [6]. Here, we characterize the coenocytic cell division cycle in the ichthyosporean Sphaeroforma arctica. We observe that, in laboratory conditions, S. arctica cells undergo a uniform and easily synchronizable coenocytic cell cycle, reaching up to 128 nuclei per cell before cellularization and release of daughter cells. Cycles of nuclear division occur synchronously within the coenocyte and in regular time intervals (11-12 hr). We find that the growth of cell volume is dependent on concentration of nutrients in the media; in contrast, the rate of nuclear division cycles is constant over a range of nutrient concentrations. Together, the results suggest that nuclear division cycles in the coenocytic growth of S. arctica are driven by a timer, which ensures periodic and synchronous nuclear cycles independent of the cell size and growth. Copyright © 2018 The Author(s). Published by Elsevier Ltd.. All rights reserved.

  12. Morphological and molecular characterization of Sarcocystis arctica-like sarcocysts from the Arctic fox (Vulpes lagopus)from Alaska, USA

    USDA-ARS?s Scientific Manuscript database

    Sarcocystis sarcocysts are common in muscles of herbivores but are rare in muscles of carnivores. Here, we report Sarcocystis arctica-like sarcocysts in muscles of Arctic foxes (Vulpes lagopus) from Alaska, USA for the first time. Tongues of 57 foxes were examined for Sarcocystis infection using sev...

  13. North Atlantic Oscillation dynamics recorded in shells of a long-lived bivalve mollusk

    NASA Astrophysics Data System (ADS)

    Schöne, Bernd R.; Oschmann, Wolfgang; Rössler, Jochen; Freyre Castro, Antuané D.; Houk, Stephen D.; Kröncke, Ingrid; Dreyer, Wolfgang; Janssen, Ronald; Rumohr, Heye; Dunca, Elena

    2003-12-01

    Existing reconstructions of the winter North Atlantic Oscillation (WNAO) are based on terrestrial proxies and historical documents. No direct high-resolution, long-term rec ords from marine settings are available for this major climate-dictating phenomenon, which severely affects a variety of economic aspects of our society. Here we present a 245 yr proxy WNAO index based on shells of the long-lived marine bivalve mollusk Arctica islandica. Variations in annual rates of shell growth are positively correlated with WNAO-related changes in the food supply. Maximum amplitudes in frequency bands of 7 9 and 5 7 yr fall exactly within the range of instrumental and other proxy WNAO indices. These estimates were obtained for specimens collected live, 2000 km apart, in the central North Sea and on the Norwegian Shelf. Hence, the WNAO influences hydrographic regimes of large regions of the ocean. Our study demonstrates that A. islandica can reliably reconstruct WNAO dynamics for time intervals and regions without instrumental records. Our new tool functions as a proxy for the WNAO index prior to the twentieth-century greenhouse forcing and has the potential to further validate other proxy-based WNAO records.

  14. Morphological and molecular characterization of Sarcocystis arctica-like sarcocysts from the Arctic fox (Vulpes lagopus) from Alaska, USA.

    PubMed

    Cerqueira-Cézar, Camila K; Thompson, Peter C; Verma, Shiv Kumar; Mowery, Joseph; Calero-Bernal, Rafael; Antunes Murata, Fernando H; Sinnett, David R; Van Hemert, Caroline; Rosenthal, Benjamin M; Dubey, Jitender P

    2017-07-01

    The muscles of herbivores commonly harbor sarcocysts of parasites belonging to species in the genus Sarcocystis, but such muscle parasites are rare in carnivores. Here, we report Sarcocystis arctica-like sarcocysts in muscles of Arctic foxes (Vulpes lagopus) from Alaska, USA, for the first time. The tongues of 56 foxes were examined for Sarcocystis infection using several methods. Sarcocystis bradyzoites were detected in pepsin digests of 13 (23.2%), and sarcocysts were found in histological sections stained with hematoxylin and eosin (HE) of 9 (16.0%). By light microscopy, sarcocysts were up to 4 mm long and up to 245 μm wide. In HE-stained sections, the sarcocyst wall appeared smooth and up to 1.5 μm thick without visible protrusions. By transmission electron microscopy, the sarcocyst wall had a wavy parasitophorous vacuolar membrane (pvm) folded as pleomorphic villar protrusions (vp), sometimes with anastomoses of villar tips. The vp and the ground substance (gs) layer were smooth and without microtubules. The gs was up to 2.0 μm thick. The total width of the wall including vp and the gs was up to 4.0 μm. The vp were up to 3.0 μm long and most closely resembled "type 9c." All sarcocysts were mature and contained numerous 8.1 × 2.1 μm sized bradyzoites. Molecular characterization (at 18S rDNA, 28S rDNA, ITS-1, and cox1) showed the highest affinity for S. arctica of the Arctic fox (V. lagopus) from Norway. In the present investigation, we provide evidence that sarcocysts are common in tongues of Alaskan Arctic foxes suggesting that these carnivores are serving as intermediate hosts, and we also provide ultrastructure of S. arctica from the Arctic fox for the first time.

  15. Morphological and molecular identification of Sarcocystis arctica sarcocysts in three red foxes (Vulpes vulpes) from the Czech Republic.

    PubMed

    Pavlásek, Ivan; Máca, Ondřej

    2017-10-01

    Muscular sarcocystosis by Sarcocystis arctica was found for the first time in the Czech Republic, in different muscles of red fox (Vulpes vulpes). Cysts were slim, elongated, thread-like, whitish, 1-7mm long, and 206-270μm wide; bradyzoites were 7.9×2.7μm in unstained wet mounts and 9.2×2.9μm in cyst Giemsa-stained smears. The cyst wall was thin, with short villi-like protrusions, and no host response was observed in the histological sections. Examination of the distribution and intensity of sarcocysts in 17 different muscle groups revealed that the highest intensity was in the cranial tibial muscle (>15 cysts in compressoria), followed by the diaphragm, forearm, and other groups (with intensities of 3-15 cysts in compressoria). Sarcocysts were detected in 3 out of 86 foxes. Genetic characterization at 18S rRNA, 28S rRNA, ITS1 and cox1, consistently showed that the species was identical with S. arctica. Interestingly, this protozoan was also detected as a co-infection in 3 foxes with the nematode Trichinella spp. for the first time. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Morphological and molecular characterization of Sarcocystis arctica-like sarcocysts from the Arctic fox (Vulpes lagopus) from Alaska, USA

    USGS Publications Warehouse

    Cerqueira-Cézar, Camila K.; Thompson, Peter C.; Verma, Shiv K.; Mowery, Joseph; Calero-Bernal, Rafael; Antunes Murata, Fernando H.; Sinnett, David R.; Van Hemert, Caroline R.; Rosenthal, Benjamin M.; Dubey, Jitender P.

    2017-01-01

    The muscles of herbivores commonly harbor sarcocysts of parasites belonging to species in the genus Sarcocystis, but such muscle parasites are rare in carnivores. Here, we report Sarcocystis arctica-like sarcocysts in muscles of Arctic foxes (Vulpes lagopus) from Alaska, USA, for the first time. The tongues of 56 foxes were examined for Sarcocystis infection using several methods. Sarcocystis bradyzoites were detected in pepsin digests of 13 (23.2%), and sarcocysts were found in histological sections stained with hematoxylin and eosin (HE) of 9 (16.0%). By light microscopy, sarcocysts were up to 4 mm long and up to 245 μm wide. In HE-stained sections, the sarcocyst wall appeared smooth and up to 1.5 μm thick without visible protrusions. By transmission electron microscopy, the sarcocyst wall had a wavy parasitophorous vacuolar membrane (pvm) folded as pleomorphic villar protrusions (vp), sometimes with anastomoses of villar tips. The vp and the ground substance (gs) layer were smooth and without microtubules. The gs was up to 2.0 μm thick. The total width of the wall including vp and the gs was up to 4.0 μm. The vp were up to 3.0 μm long and most closely resembled “type 9c.” All sarcocysts were mature and contained numerous 8.1 × 2.1 μm sized bradyzoites. Molecular characterization (at 18S rDNA, 28S rDNA, ITS-1, and cox1) showed the highest affinity for S. arctica of the Arctic fox (V. lagopus) from Norway. In the present investigation, we provide evidence that sarcocysts are common in tongues of Alaskan Arctic foxes suggesting that these carnivores are serving as intermediate hosts, and we also provide ultrastructure of S. arctica from the Arctic fox for the first time.

  17. Differential immune response in the hard clam (mercenaria mercenaria) against bacteria and the protistan pathogen QPX (quahog parasite unknown).

    PubMed

    Perrigault, Mickael; Allam, Bassem

    2012-06-01

    The immune response of the hard clam (quahog) Mercenaria mercenaria following challenge with live bacteria (Vibrio alginolyticus) and the protist QPX (Quahog Parasite Unknown) was investigated. The study also compared immune responses following QPX challenge in two different hard clam broodstocks exhibiting different degrees of susceptibility toward this parasite. Different immune and stress-related cellular and humoral factors were assessed including general hemocyte parameters (total and differential hemocyte counts, percentage of dead cells, reactive oxygen production, phagocytosis), parameters geared toward QPX (anti-QPX activity in plasma and hemocyte resistance to the cytotoxicity of QPX extracellular products). Two genes (ferritin and metallothionein) previously shown to be modulated following QPX exposure were molecularly characterized by rapid amplification of cDNA ends (RACE) and their transcription levels were determined in resistant and susceptible clams in response to QPX and bacterial challenge. Results indicated that both V. alginolyticus and QPX challenge triggered significant immune responses in clams with similar trends for most measured parameters. However, specific responses were observed for anti-QPX activity in plasma and hemocyte resistance to QPX products as well as ferritin and metallothionein expression according to each inoculum. Similarly, different response patterns were detected following QPX challenge in susceptible and resistant clam stocks. Resistant clams were able to elicit effective response against the parasite leading to the elimination of QPX and the restoration of constitutive immune status whereas QPX-susceptible clams triggered a strong immune modulation characterized by an acute phase response and associated acute phase protein but appeared to be less active in eliminating the parasite. These results suggest that different signaling pathways are triggered during V. alginolyticus and QPX challenge. Moreover, differences in

  18. Climatic variability in sclerochronological records from the northern North Sea

    NASA Astrophysics Data System (ADS)

    Trofimova, T.; Andersson Dahl, C.; Bonitz, F. G. W.

    2016-12-01

    Highly resolved palaeoreconstructions that can extend instrumental records back through time is a fundament for our understanding of a climate of the last millennia. Only a few established extratropical marine paleo archives enable the reconstruction of key ocean processes at annual to sub-annual time scales. Bivalves have been shown to provide a useful archive with high temporal resolution. The species Arctica islandica is unique proxy due to its exceptional longevity combined with sensitivity to changes in environmental conditions. In this study, we investigate the impact of climate variability on sclerochronological records of A. islandica from the Viking Bank in the northern North Sea. The hydrographical characteristics of this location are mainly controlled by the major inflow of Atlantic water in the North Sea and can potentially be reflected in the shell composition and growth of A. islandica. To reconstruct environment conditions, we use shells of living and subfossil specimens of A. islandica collected by dredging at depths around 100 meters. The annual growth bands within the shells were determined and growth increments widths were measured. By cross-matching 30 individual increment-width time series, we built an absolutely dated 265-year long shell-growth chronology spanning the time interval 1748-2013 AD. The relatively high Rbar (>0.5) and EPS (>0.85) values indicate a common environmental forcing on the shell growth within the population. The growth chronology preserves a 20-30 yr variability prior to 1900 which fades out towards the present. That change suggests a possible regime shift at the beginning of a 20th century. Ongoing work mainly focuses on comparing the shell-growth chronology with existing observational time series of climatic parameters to determine controlling factors and test the use of growth chronologies for climate reconstruction in this area. For reconstructing seasonality, we analyse the stable oxygen isotope composition of the

  19. ER-2 #809 and DC-8 in Arena Arctica hangar in Kiruna, Sweden prior to the SAGE III Ozone Loss and Validation Experiment (SOLVE)

    NASA Image and Video Library

    2000-01-23

    NASA ER-2 # 809 and its DC-8 shown in Arena Arctica before the SAGE III Ozone Loss and Validation Experiment (SOLVE). The two airborne science platforms were based north of the Arctic Circle in Kiruna, Sweden, during the winter of 2000 to study ozone depletion as part of SOLVE. A large hangar built especially for research, "Arena Arctica" housed the instrumented aircraft and the scientists. Scientists have observed unusually low levels of ozone over the Arctic during recent winters, raising concerns that ozone depletion there could become more widespread as in the Antarctic ozone hole. The NASA-sponsored international mission took place between November 1999 and March 2000 and was divided into three phases. The DC-8 was involved in all three phases returning to Dryden between each phase. The ER-2 flew sample collection flights between January and March, remaining in Sweden from Jan. 9 through March 16. "The collaborative campaign will provide an immense new body of information about the Arctic stratosphere," said program scientist Dr. Michael Kurylo, NASA Headquarters. "Our understanding of the Earth's ozone will be greatly enhanced by this research."

  20. Annually resolved North Atlantic marine climate over the last millennium

    NASA Astrophysics Data System (ADS)

    Reynolds, D. J.; Scourse, J. D.; Halloran, P. R.; Nederbragt, A. J.; Wanamaker, A. D.; Butler, P. G.; Richardson, C. A.; Heinemeier, J.; Eiríksson, J.; Knudsen, K. L.; Hall, I. R.

    2016-12-01

    Owing to the lack of absolutely dated oceanographic information before the modern instrumental period, there is currently significant debate as to the role played by North Atlantic Ocean dynamics in previous climate transitions (for example, Medieval Climate Anomaly-Little Ice Age, MCA-LIA). Here we present analyses of a millennial-length, annually resolved and absolutely dated marine δ18O archive. We interpret our record of oxygen isotope ratios from the shells of the long-lived marine bivalve Arctica islandica (δ18O-shell), from the North Icelandic shelf, in relation to seawater density variability and demonstrate that solar and volcanic forcing coupled with ocean circulation dynamics are key drivers of climate variability over the last millennium. During the pre-industrial period (AD 1000-1800) variability in the sub-polar North Atlantic leads changes in Northern Hemisphere surface air temperatures at multi-decadal timescales, indicating that North Atlantic Ocean dynamics played an active role in modulating the response of the atmosphere to solar and volcanic forcing.

  1. History of bioavailable lead and iron in the Greater North Sea and Iceland during the last millennium - a bivalve sclerochronological reconstruction.

    PubMed

    Holland, Hilmar A; Schöne, Bernd R; Marali, Soraya; Jochum, Klaus P

    2014-10-15

    We present the first annually resolved record of biologically available Pb and Fe in the Greater North Sea and Iceland during 1040-2004 AD based on shells of the long-lived marine bivalve Arctica islandica. The iron content in pre-industrial shells from the North Sea largely remained below the detection limit. Only since 1830, shell Fe levels rose gradually reflecting the combined effect of increased terrestrial runoff of iron-bearing sediments and eutrophication. Although the lead gasoline peak of the 20th century was well recorded by the shells, bivalves that lived during the medieval heyday of metallurgy showed four-fold higher shell Pb levels than modern specimens. Presumably, pre-industrial bivalves were offered larger proportions of resuspended (Pb-enriched) organics, whereas modern specimens receive fresh increased amounts of (Pb-depleted) phytoplankton. As expected, metal loads in the shells from Iceland were much lower. Our study confirms that bivalve shells provide a powerful tool for retrospective environmental biomonitoring. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. Identification of clam plasma proteins that bind its pathogen Quahog Parasite Unknown.

    PubMed

    Hartman, Rachel; Pales Espinosa, Emmanuelle; Allam, Bassem

    2018-06-01

    The hard clam (Mercenaria mercenaria) is among the most economically-important marine species along the east coast of the United States, representing the first marine resource in several Northeastern states. The species is rather resilient to infections and the only important disease of hard clams results from an infection caused by Quahog Parasite Unknown (QPX), a protistan parasite that can lead to significant mortality events in wild and aquacultured clam stocks. Though the presence of QPX disease has been documented since the 1960s, little information is available on cellular and molecular interactions between the parasite and the host. This study examined the interactions between the clam immune system and QPX cells. First, the effect of clam plasma on the binding of hemocytes to parasite cells was evaluated. Second, clam plasma proteins that bind QPX cells were identified through proteomic (LC-MS/MS) analyses. Finally, the effect of prior clam exposure to QPX on the abundance of QPX-reactive proteins in the plasma was evaluated. Results showed that plasma factors enhance the attachment of hemocytes to QPX. Among the proteins that specifically bind to QPX cells, several lectins were identified, as well as complement component proteins and proteolytic enzymes. Furthermore, results showed that some of these lectins and complement-related proteins are inducible as their abundance significantly increased following QPX challenge. These results shed light on plasma proteins involved in the recognition and binding of parasite cells and provide molecular targets for future investigations of factors involved in clam resistance to the disease, and ultimately for the selection of resistant clam stocks. Copyright © 2018 Elsevier Ltd. All rights reserved.

  3. Terrimonas arctica sp. nov., isolated from Arctic tundra soil.

    PubMed

    Jiang, Fan; Qiu, Xia; Chang, Xulu; Qu, Zhihao; Ren, Lvzhi; Kan, Wenjing; Guo, Youhao; Fang, Chengxiang; Peng, Fang

    2014-11-01

    A novel, Gram-stain-negative, aerobic, non-motile and rod-shaped bacterium, designated R9-86(T), was isolated from tundra soil collected near Ny-Ålesund, Svalbard Archipelago, Norway (78° N). Growth occurred at 4-28 °C (optimum, 22-25 °C) and at pH 6.0-9.0 (optimum, pH 7.0). Flexirubin-type pigments were absent. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain R9-86(T) belonged to the genus Terrimonas in the family Chitinophagaceae. 16S rRNA gene sequence similarities between strain R9-86(T) and the type strains of species of the genus Terrimonas with validly published names ranged from 93.7 to 95.0%. Strain R9-86(T) contained iso-C(15:1)-G (25.7%), iso-C(15:0) (24.5%), iso-C(17:0)-3OH (18.3%) and summed feature 3 (C(16:1)ω7c and/or C(16:1)ω6c, 8.7%) as its major cellular fatty acids; phosphatidylethanolamine and an unknown polar lipid as its main polar lipids, and MK-7 as its predominant respiratory quinone. The DNA G+C content was 48.4 mol%. On the basis of phenotypic, chemotaxonomic and phylogenetic data, strain R9-86(T) is considered to represent a novel species of the genus Terrimonas, for which the name Terrimonas arctica sp. nov. is proposed. The type strain is R9-86(T) ( =CCTCC AB 2011004(T) =NRRL B-59114(T)). © 2014 IUMS.

  4. DC-8 being pushed out of the Arena Arctica hangar in Kiruna, Sweden for the second flight of the SAG

    NASA Technical Reports Server (NTRS)

    2000-01-01

    This photo shows NASA's DC-8 being pushed out of the Arena Arctica hangar in Kiruna, Sweden for the second flight of the SAGE III Ozone Loss and Validation Experiment (SOLVE). One of Dryden's high-flying ER-2 Airborne Science aircraft, a civilian variant of Lockheed's U-2, and another NASA flying laboratory, Dryden's DC-8, were based north of the Arctic Circle in Kiruna, Sweden during the winter of 2000 to study ozone depletion as part of SOLVE. A large hangar built especially for research, 'Arena Arctica' housed the instrumented aircraft and the scientists. Scientists observed unusually low levels of ozone over the Arctic during recent winters, raising concerns that ozone depletion there could become more widespread as in the Antarctic ozone hole. The NASA-sponsored international mission took place between November 1999 and March 2000 and was divided into three phases. The DC-8 was involved in all three phases returning to Dryden between each phase. The ER-2 flew science collection flights between January and March, remaining in Sweden from Jan. 9 through March 16. 'The collaborative campaign will provide an immense new body of information about the Arctic stratosphere,' said program scientist Dr. Michael Kurylo, NASA Headquarters. 'Our understanding of the Earth's ozone will be greatly enhanced by this research.' NASA is using a DC-8 aircraft as a flying science laboratory. The platform aircraft, based at NASA's Dryden Flight Research Center, Edwards, Calif., collects data for many experiments in support of scientific projects serving the world scientific community. Included in this community are NASA, federal, state, academic and foreign investigators. Data gathered by the DC-8 at flight altitude and by remote sensing have been used for scientific studies in archeology, ecology, geography, hydrology, meteorology, oceanography, volcanology, atmospheric chemistry, soil science and biology.

  5. A blood survey of elements, viral antibodies, and hemoparasites in wintering Harlequin Ducks (Histrionicus histrionicus) and Barrow's Goldeneyes (Bucephala islandica)

    USGS Publications Warehouse

    Heard, D.J.; Mulcahy, D.M.; Iverson, S.A.; Rizzolo, D.J.; Greiner, E.C.; Hall, J.; Ip, Hon S.; Esler, Daniel N.

    2008-01-01

    Twenty-eight Harlequin Ducks (Histrionicus histrionicus) and 26 Barrow's Goldeneyes (Bucephala islandica) were captured in Prince William Sound, Alaska, between 1 and 15 March 2005. Blood was collected for quantification of element concentrations, prevalence of antibodies to several viruses, and hemoparasite prevalence and identification. Although we found selenium concentrations that have been associated with selenosis in some birds (???.0 ppm ww), our findings contribute to a growing literature describing relatively high selenium in apparently healthy birds in marine environments. Avian influenza virus antibodies were detected in the plasma of 28% of the ducks. No antibodies against adenovirus, reovirus, or paramyxovirus 1 were detected. Several hemoparasite species were identified in 7% of ducks. Our findings are similar to those in other free-living marine waterfowl and do not indicate unusual concerns for the health of these species in this area in late winter. ?? Wildlife Disease Association 2008.

  6. A blood survey of elements, viral antibodies, and hemoparasites in wintering Harlequin Ducks (Histrionicus histrionicus) and Barrow's Goldeneyes (Bucephala islandica).

    PubMed

    Heard, Darryl J; Mulcahy, Daniel M; Iverson, Samuel A; Rizzolo, Daniel J; Greiner, Ellis C; Hall, Jeff; Ip, Hon; Esler, Daniel

    2008-04-01

    Twenty-eight Harlequin Ducks (Histrionicus histrionicus) and 26 Barrow's Goldeneyes (Bucephala islandica) were captured in Prince William Sound, Alaska, between 1 and 15 March 2005. Blood was collected for quantification of element concentrations, prevalence of antibodies to several viruses, and hemoparasite prevalence and identification. Although we found selenium concentrations that have been associated with selenosis in some birds (>or=2.0 ppm ww), our findings contribute to a growing literature describing relatively high selenium in apparently healthy birds in marine environments. Avian influenza virus antibodies were detected in the plasma of 28% of the ducks. No antibodies against adenovirus, reovirus, or paramyxovirus 1 were detected. Several hemo-parasite species were identified in 7% of ducks. Our findings are similar to those in other free-living marine waterfowl and do not indicate unusual concerns for the health of these species in this area in late winter.

  7. A Large Ornithurine Bird (Tingmiatornis arctica) from the Turonian High Arctic: Climatic and Evolutionary Implications

    NASA Astrophysics Data System (ADS)

    Bono, Richard K.; Clarke, Julia; Tarduno, John A.; Brinkman, Donald

    2016-12-01

    Bird fossils from Turonian (ca. 90 Ma) sediments of Axel Heiberg Island (High Canadian Arctic) are among the earliest North American records. The morphology of a large well-preserved humerus supports identification of a new volant, possibly diving, ornithurine species (Tingmiatornis arctica). The new bird fossils are part of a freshwater vertebrate fossil assemblage that documents a period of extreme climatic warmth without seasonal ice, with minimum mean annual temperatures of 14 °C. The extreme warmth allowed species expansion and establishment of an ecosystem more easily able to support large birds, especially in fresh water bodies such as those present in the Turonian High Arctic. Review of the high latitude distribution of Northern Hemisphere Mesozoic birds shows only ornithurine birds are known to have occupied these regions. We propose physiological differences in ornithurines such as growth rate may explain their latitudinal distribution especially as temperatures decline later in the Cretaceous. Distribution and physiology merit consideration as factors in their preferential survival of parts of one ornithurine lineage, Aves, through the K/Pg boundary.

  8. Roseomonas arctica sp. nov., isolated from arctic glacial foreland soil.

    PubMed

    Qiu, Xia; Qu, Zhihao; Jiang, Fan; Lin, Yingjun; Zhang, Yumin; Chang, Xulu; Da, Xuyang; Deng, Sangsang; Kim, Myongchol; Fang, Chengxiang; Peng, Fang

    2016-03-01

    A novel psychrotolerant bacterium, designed strain M6-79 T , was isolated from an arctic glacial foreland soil sample collected from Ny-Ålesund in the Svalbard Archipelago, Norway. Cells of strain M6-79 T were Gram-stain-negative, rod-shaped and produced a red-pigment. Strain M6-79 T was strictly aerobic, non-motile, non-endospore-forming, oxidase-negative and catalase-positive. Based on 16S rRNA gene sequence analysis, strain M6-79 T was phylogenetically related to Roseomonas aquatica TR53 T (95.2 % 16S rRNA gene sequence similarity), Roseomonas lacus TH-G33 T (94.3 %), ' Roseomonas sediminicola' FW-3 (94.3 %), Roseomonas terrae DS-48 T (94.1 %) and Roseomonas soli 5N26 T (94.1 %). The unique isoprenoid quinone detected in strain M6-79 T was Q-9. The polar lipid profile consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, one unknown aminolipid and one unknown lipid. Strain M6-79 T possessed C 18 : 1 ω7 c , C 16 : 0 and summed feature 3 (C 16 : 1 ω6 c and/or C 16 : 1 ω7 c ) as the predominant fatty acids, and the DNA G+C content was 71.2 mol%. Combined data from phylogenetic, phenotypic and chemotaxonomic studies revealed that strain M6-79 T represents a novel species of the genus Roseomonas , for which the name Roseomonas arctica sp. nov. is proposed. The type strain is strain M6-79 T ( = CCTCC AB 2013101 T  = LMG 28251 T ).

  9. Reconstructing Holocene seasonal hydrographic variability in the eastern North Atlantic using bivalve shells from St Kilda, Scotland

    NASA Astrophysics Data System (ADS)

    Alexandroff, Stella; Scourse, James; Butler, Paul; Schöne, Bernd; Reimer, Paula

    2017-04-01

    Bivalve shells like Arctica islandica and Glycymeris glycymeris can be used as highly resolved archives of past marine climate and long-term biomonitors. The annual growth patterns of the shell reflect the environment the animals live in and by cross-matching these growth patterns it is possible to construct multi-centennial, annually resolved chronologies that form a temporal template for isotope sampling. The aim of this study is to detect a signal of Atlantic hydrographic variability in Scottish Shelf Seas that is as far as possible uncontaminated by other influences. In May 2014, we collected dead valves and young live specimens of G. glycymeris from St Kilda, Outer Hebrides, Scotland, and in April 2016, live specimens of A. islandica were collected at the same location. This area is of particular interest as it is close to the Scottish shelf margin, has negligible freshwater input, and is thought to represent open-ocean North Atlantic signals well. We here present two floating chronologies, each spanning >180 years, built from dead-collected G. glycymeris shells from St Kilda. All the shells in these chronologies were assigned radiocarbon ages between 3700-3300 cal yr BP. By combining the radiocarbon dates and the chronological data derived from cross-matching annual bands in the shells, one of the floating chronologies could be further constrained to 3750-3500 cal yr BP (95% range). Sub-annual δ18O data from the floating chronologies and from the modern specimens show a strong seasonal signal and multi-year trends. We calibrate the δ18O results from the modern specimens with instrumental data, which enables us (subject to the assumption that there has been no change in δ18Owater) to compare mean and seasonal seawater temperatures between the present day and the fourth millennium BP.

  10. Effects of the red tide dinoflagellate, Karenia brevis, on early development of the eastern oyster Crassostrea virginica and northern quahog Mercenaria mercenaria.

    PubMed

    Rolton, Anne; Vignier, Julien; Soudant, Philippe; Shumway, Sandra E; Bricelj, V Monica; Volety, Aswani K

    2014-10-01

    The brevetoxin-producing dinoflagellate, Karenia brevis, adversely affects many shellfish species including the commercially and ecologically important bivalve molluscs, the northern quahog (=hard clam) Mercenaria mercenaria and eastern oyster Crassostrea virginica, in the Gulf of Mexico, USA. This study assessed the effects of exposure of these bivalves to K. brevis during their early development. In separate experiments, embryos of 2-4 cell stage of M. mercenaria and C. virginica were exposed to both whole and lysed K. brevis cells isolated from Manasota Key, Florida. Low bloom concentrations of 500 to 3000 cells mL(-1) were simulated for 96 h. Shell length, percent abnormality (and normality), and percent mortality of resulting larvae were measured. Percentages were recorded after 6, 24, and 96 h of exposure; larval shell length was measured at 24 and 96 h. For both quahogs and oysters, the effects of exposing embryos to K. brevis on all larval responses were generally dose- and time-dependent. Percent mortalities and abnormalities of both clam and oyster embryos increased significantly after only 6h of exposure to whole cells of K. brevis. For clams, these parameters were significantly higher in whole and lysed treatments (at 3000 cells mL(-1)) than in controls. Percent mortalities of oysters were significantly higher in the whole-cell treatment (3000 cells mL(-1)) than under control conditions. After 24h of exposure, mean larval shell length of both bivalve species was significantly reduced relative to controls. This was evident for clam larvae in both the lysed treatment at 1500 cells mL(-1) and in whole and lysed treatments at 3000 cells mL(-1), and for oyster larvae in the lysed treatment at 3000 cells mL(-1). After 96 h, both species exposed to the lysed cell treatment at 3000 cells mL(-1) had significantly smaller larvae compared to those in the control. Overall, lysed cells of K. brevis had a more pronounced effect on shell length, percent abnormality

  11. Toward a Reconstruction of the Atlantic Multidecadal Oscillation Using Shell-based Records from Coastal Northern Norway

    NASA Astrophysics Data System (ADS)

    Mette, M.; Wanamaker, A. D.; Carroll, M.; Ambrose, W. G., Jr.; Retelle, M.

    2016-02-01

    North Atlantic sea surface temperatures over the past 150 years have exhibited multidecadal variability, switching between relatively warm and cool periods, described by the Atlantic Multidecadal Oscillation (AMO). The influence, persistence, and causes of the AMO, however, are debated because instrumental records of North Atlantic sea surface temperatures only capture 2 cycles of this 60 to 80 year mode. Thus far, AMO reconstructions have been largely based on terrestrial archives despite the fact that the AMO is an oceanic mode. Proxy records from the marine realm are therefore necessary to better understand the behavior of the AMO over recent centuries. We present continuous, annual shell-based records of oxygen isotopes and growth from the long-lived marine bivalve Arctica islandica from coastal northern Norway (71 °N) from 1900-2012 that strongly relate to the instrumental AMO record (r = -0.59, p < 0.01). We performed calibration/verification analysis in order to assess the potential for these records to contribute to AMO reconstructions. We also compare our record with other proxy reconstructions of AMO variability over the past century. Our results show that extending shell-based records to past centuries will provide valuable information about AMO variability.

  12. 75 FR 81142 - Magnuson-Stevens Fishery Conservation and Management Act Provisions; Fisheries of the...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-27

    ...; Fisheries of the Northeastern United States; Atlantic Surfclam and Ocean Quahog Fishery; Final 2011-2013 Fishing Quotas for Atlantic Surfclam and Ocean Quahog AGENCY: National Marine Fisheries Service (NMFS... implements final quotas for the Atlantic surfclam and ocean quahog fisheries for 2011, 2012, and 2013...

  13. 50 CFR 648.72 - Minimum surf clam size.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Atlantic Surf Clam and Ocean Quahog Fisheries § 648.72 Minimum surf clam size. Link to an amendment... quahog specifications. (a) Establishing catch quotas. The amount of surfclams or ocean quahogs that may... paragraph (b) of this section. The amount of surfclams available for harvest annually must be specified...

  14. 77 FR 64488 - Magnuson-Stevens Fishery Conservation and Management Act Provisions; Fisheries of the...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-22

    ... portion of the Georges Bank Closed Area to the harvest of Atlantic surfclams and ocean quahogs. The full...; Atlantic Surfclam and Ocean Quahog Fishery AGENCY: National Marine Fisheries Service (NMFS), National... closed to the harvest of surfclams and ocean quahogs since 1990 due to red tide blooms that cause...

  15. 50 CFR 648.6 - Dealer/processor permits.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... deep-sea red crab, spiny dogfish, summer flounder, Atlantic surf clam, ocean quahog, Atlantic mackerel, squid, butterfish, scup, bluefish, tilefish, and black sea bass; Atlantic surf clam and ocean quahog... business if applying for a surf clam and ocean quahog permit), mailing address(es) and telephone number(s...

  16. 50 CFR 648.75 - Cage identification.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Atlantic Surf Clam and Ocean Quahog Fisheries § 648.75 Cage identification. Link to an amendment published.... Before offloading, all cages that contain surfclams or ocean quahogs must be tagged with tags acquired...) Observers. (i) The Regional Administrator may allow the shucking of surfclams or ocean quahogs at sea if he...

  17. 50 CFR 648.77 - Framework adjustments to management measures.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Management Measures for the Atlantic Surf Clam and Ocean Quahog Fisheries § 648.77 Framework adjustments to... the Atlantic Surf Clam and Ocean Quahog FMP if it finds that action is necessary to meet or be... fishing permit for surfclams and ocean quahogs: (a) Tagging. Before offloading, all cages that contain...

  18. 77 FR 31332 - Mid-Atlantic Fishery Management Council (MAFMC); Public Meetings

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-25

    ... consider changes to the 2013 quota specifications for surfclams and ocean quahogs and update PSP, data..., Mackerel, Squid, and Butterfish Committee, and its Surfclam, Ocean Quahog Committee will hold public... (Amendment 14) from 1 p.m. until 3 p.m. The Surfclam and Ocean Quahog Committee will meet as a Committee of...

  19. 50 CFR 648.15 - Facilitation of enforcement.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... surfclam and ocean quahog vessel owners and operators. (1) Surfclam and ocean quahog open access permitted vessels. Vessel owners or operators issued an open access surfclam or ocean quahog open access permit for.../or an Open Access Herring Permit that fished with midwater trawl gear pursuant to § 648.80(d). Such...

  20. 50 CFR 648.77 - Cage identification.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Atlantic Surf Clam and Ocean Quahog Fisheries § 648.77 Cage identification. Except as provided in § 648.78... for surfclams and ocean quahogs: (a) Tagging. Before offloading, all cages that contain surfclams or... Administrator. (g) Transfer. See § 648.74(b)(2). (h) Presumptions. Surfclams and ocean quahogs found in cages...

  1. 50 CFR 648.77 - Cage identification.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Atlantic Surf Clam and Ocean Quahog Fisheries § 648.77 Cage identification. Except as provided in § 648.78... for surfclams and ocean quahogs: (a) Tagging. Before offloading, all cages that contain surfclams or... Administrator. (g) Transfer. See § 648.74(b)(2). (h) Presumptions. Surfclams and ocean quahogs found in cages...

  2. 50 CFR 648.77 - Cage identification.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Atlantic Surf Clam and Ocean Quahog Fisheries § 648.77 Cage identification. Except as provided in § 648.78... for surfclams and ocean quahogs: (a) Tagging. Before offloading, all cages that contain surfclams or... Administrator. (g) Transfer. See § 648.74(b)(2). (h) Presumptions. Surfclams and ocean quahogs found in cages...

  3. Fungal colonization and decomposition of leaves and stems of Salix arctica on deglaciated moraines in high-Arctic Canada

    NASA Astrophysics Data System (ADS)

    Osono, Takashi; Matsuoka, Shunsuke; Hirose, Dai; Uchida, Masaki; Kanda, Hiroshi

    2014-06-01

    Fungal colonization, succession, and decomposition of leaves and stems of Salix arctica were studied to estimate the roles of fungi in the decomposition processes in the high Arctic. The samples were collected from five moraines with different periods of development since deglaciation to investigate the effects of ecosystem development on the decomposition processes during the primary succession. The total hyphal lengths and the length of darkly pigmented hyphae increased during decomposition of leaves and stems and were not varied with the moraines. Four fungal morphotaxa were frequently isolated from both leaves and stems. The frequencies of occurrence of two morphotaxa varied with the decay class of leaves and/or stems. The hyphal lengths and the frequencies of occurrence of fungal morphotaxa were positively or negatively correlated with the contents of organic chemical components and nutrients in leaves and stems, suggesting the roles of fungi in chemical changes in the field. Pure culture decomposition tests demonstrated that the fungal morphotaxa were cellulose decomposers. Our results suggest that fungi took part in the chemical changes in decomposing leaves and stems even under the harsh environment of the high Arctic.

  4. Neisseria arctica sp. nov. isolated from nonviable eggs of greater white-fronted geese (Anser albifrons) in Arctic Alaska

    USGS Publications Warehouse

    Hansen, Cristina M.; Himschoot, Elizabeth; Hare, Rebekah F.; Meixell, Brandt W.; Van Hemert, Caroline R.; Hueffer, Karsten

    2017-01-01

    During the summers of 2013 and 2014, isolates of a novel Gram-negative coccus in the Neisseria genus were obtained from the contents of nonviable greater white-fronted goose (Anser albifrons) eggs on the Arctic Coastal Plain of Alaska. We used a polyphasic approach to determine whether these isolates represent a novel species. 16S rRNA gene sequences, 23S rRNA gene sequences, and chaperonin 60 gene sequences suggested that these Alaskan isolates are members of a distinct species that is most closely related to Neisseria canis, N. animaloris, and N. shayeganii. Analysis of the rplF gene additionally showed that our isolates are unique and most closely related to N. weaveri. Average nucleotide identity of the whole genome sequence of our type strain was between 71.5% and 74.6% compared to close relatives, further supporting designation as a novel species. Fatty acid methyl ester analysis showed a predominance of C14:0, C16:0, and C16:1ω7c fatty acids. Finally, biochemical characteristics distinguished our isolates from other Neisseria species. The name Neisseria arctica (type strain KH1503T = ATCC TSD-57T = DSM 103136T) is proposed.

  5. 50 CFR 648.70 - Annual individual allocations.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... text is set forth as follows: § 648.70 Surfclam and ocean quahog Annual Catch Limit (ACL). (a) The... established consistent with the guidelines contained in the Atlantic Surfclam and Ocean Quahog FMP. The ACL... ACLs at least every 5 years. (1) If the surfclam or the ocean quahog ACL is exceeded with a frequency...

  6. The complete sequences and gene organisation of the mitochondrial genomes of the heterodont bivalves Acanthocardia tuberculata and Hiatella arctica – and the first record for a putative Atpase subunit 8 gene in marine bivalves

    PubMed Central

    Dreyer, Hermann; Steiner, Gerhard

    2006-01-01

    Background Mitochondrial (mt) gene arrangement is highly variable among molluscs and especially among bivalves. Of the 30 complete molluscan mt-genomes published to date, only one is of a heterodont bivalve, although this is the most diverse taxon in terms of species numbers. We determined the complete sequence of the mitochondrial genomes of Acanthocardia tuberculata and Hiatella arctica, (Mollusca, Bivalvia, Heterodonta) and describe their gene contents and genome organisations to assess the variability of these features among the Bivalvia and their value for phylogenetic inference. Results The size of the mt-genome in Acanthocardia tuberculata is 16.104 basepairs (bp), and in Hiatella arctica 18.244 bp. The Acanthocardia mt-genome contains 12 of the typical protein coding genes, lacking the Atpase subunit 8 (atp8) gene, as all published marine bivalves. In contrast, a complete atp8 gene is present in Hiatella arctica. In addition, we found a putative truncated atp8 gene when re-annotating the mt-genome of Venerupis philippinarum. Both mt-genomes reported here encode all genes on the same strand and have an additional trnM. In Acanthocardia several large non-coding regions are present. One of these contains 3.5 nearly identical copies of a 167 bp motive. In Hiatella, the 3' end of the NADH dehydrogenase subunit (nad)6 gene is duplicated together with the adjacent non-coding region. The gene arrangement of Hiatella is markedly different from all other known molluscan mt-genomes, that of Acanthocardia shows few identities with the Venerupis philippinarum. Phylogenetic analyses on amino acid and nucleotide levels robustly support the Heterodonta and the sister group relationship of Acanthocardia and Venerupis. Monophyletic Bivalvia are resolved only by a Bayesian inference of the nucleotide data set. In all other analyses the two unionid species, being to only ones with genes located on both strands, do not group with the remaining bivalves. Conclusion The two mt

  7. ER-2 #809 and DC-8 in Arena Arctica hangar in Kiruna, Sweden prior to the SAGE III Ozone Loss and Va

    NASA Technical Reports Server (NTRS)

    2000-01-01

    NASA ER-2 # 809 and its DC-8 shown in Arena Arctica before the SAGE III Ozone Loss and Validation Experiment (SOLVE). The two airborne science platforms were based north of the Arctic Circle in Kiruna, Sweden, during the winter of 2000 to study ozone depletion as part of SOLVE. A large hangar built especially for research, 'Arena Arctica' housed the instrumented aircraft and the scientists. Scientists have observed unusually low levels of ozone over the Arctic during recent winters, raising concerns that ozone depletion there could become more widespread as in the Antarctic ozone hole. The NASA-sponsored international mission took place between November 1999 and March 2000 and was divided into three phases. The DC-8 was involved in all three phases returning to Dryden between each phase. The ER-2 flew sample collection flights between January and March, remaining in Sweden from Jan. 9 through March 16. 'The collaborative campaign will provide an immense new body of information about the Arctic stratosphere,' said program scientist Dr. Michael Kurylo, NASA Headquarters. 'Our understanding of the Earth's ozone will be greatly enhanced by this research.' ER-2s bearing tail numbers 806 and 809 are used as airborne science platforms by NASA's Dryden Flight Research Center. The aircraft are platforms for a variety of high-altitude science missions flown over various parts of the world. They are also used for earth science and atmospheric sensor research and development, satellite calibration and data validation. The ER-2s are capable of carrying a maximum payload of 2,600 pounds of experiments in a nose bay, the main equipment bay behind the cockpit, two wing-mounted superpods and small underbody and trailing edges. Most ER-2 missions last about six hours with ranges of about 2,200 nautical miles. The aircraft typically fly at altitudes above 65,000 feet. On November 19, 1998, an ER-2 set a world record for medium weight aircraft reaching an altitude of 68,700 feet. The

  8. 75 FR 66070 - Magnuson-Stevens Act Provisions; General Provisions for Domestic Fisheries; Application for...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-27

    ... of harvesting surfclams and ocean quahogs from the Atlantic surfclam and ocean quahog Georges Bank... endorsed by the U.S. Food and Drug Administration (FDA). The Assistant Regional Administrator has also made...

  9. 50 CFR 648.74 - Annual individual allocations.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Measures for the Atlantic Surf Clam and Ocean Quahog Fisheries § 648.74 Annual individual allocations. (a... surfclams and ocean quahogs for the next fishing year for each allocation holder owning an allocation...

  10. 50 CFR 648.74 - Annual individual allocations.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Measures for the Atlantic Surf Clam and Ocean Quahog Fisheries § 648.74 Annual individual allocations. (a... surfclams and ocean quahogs for the next fishing year for each allocation holder owning an allocation...

  11. 50 CFR 648.74 - Annual individual allocations.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Measures for the Atlantic Surf Clam and Ocean Quahog Fisheries § 648.74 Annual individual allocations. (a... surfclams and ocean quahogs for the next fishing year for each allocation holder owning an allocation...

  12. 50 CFR 648.70 - Annual individual allocations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Measures for the Atlantic Surf Clam and Ocean Quahog Fisheries § 648.70 Annual individual allocations. (a... surfclams and ocean quahogs for the next fishing year for each allocation holder owning an allocation...

  13. 50 CFR 648.77 - Framework adjustments to management measures.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Management Measures for the Atlantic Surf Clam and Ocean Quahog Fisheries § 648.77 Framework adjustments to... add or adjust management measures within the Atlantic Surf Clam and Ocean Quahog FMP if it finds that...

  14. Isoleucine epimerization in the high-molecular-weight fraction of pleistocene Arctica

    NASA Astrophysics Data System (ADS)

    Kaufman, Darrell S.; Sejrup, Hans-Petter

    The extent of amino acid racemization, as traditionally determined in the entire (total acid hydrolysate) pool of amino acids comprising the organic remains of fossils, is a function of the integrated effects of a complex diagenetic reaction network. We investigated the possibility that some of the complications involved in protein diagenesis might be circumvented by isolating one component of the reaction network and studying the extent of racemization in that fraction alone. We used gel-filtration to extract the high-molecular-weight (HMW) fraction of proteinaceous matter from fossil and modem molluscan shells. This fraction contains the largest (ca. > 15,000 MW), most-pristine macromolecules and has been less affected by diagenesis than the more-degraded, lower molecular-weight fractions. Variations in the extent of racemization (isoleucine epimerization; alle/Ile) measured in the HMW fraction of subsamples taken along cross sections of Arctica shells from two interglacial sites, Bø and Fjøsanger, southwestern Norway, are within the range of analytical uncertainty [coefficient of variation (cv) = 5-8%], despite the strong gradient (cv = 20-24%) in alle/Ile of the total amino acid population. Because there is no age difference across a shell, this finding supports the idea that the HMW fraction contains more geochronologically reliable proteinaceous matter than the total amino acid pool. Weighted mean alle/Ile ratios in the HMW fraction of aliquots of powdered sample from the two shells overlap at ± 1σ, despite significantly different alle/Ile ratios in the total amino acid population of some shells from the two sites. The difference in alle/Ile ratios in the total population is attributed to a greater proportion of low-molecular-weight (ca. 300 MW), and hence, extensively epimerized molecules measured in gel-filtered samples from the Fjøsanger shell. Because the rate of epimerization in the HMW fraction is much lower than in the total population, the

  15. Molluscan sclerochronology on the Faroese Shelf and its potential to obtain closer insights into the climate variability of North Atlantic water masses

    NASA Astrophysics Data System (ADS)

    Bonitz, F. G. W.; Andersson Dahl, C.; Trofimova, T.

    2016-12-01

    In this study, we investigate the climate variability in the North Atlantic during the last 350 years by applying sclerochronological methods. The inflow of North Atlantic water masses into the Arctic and the Norwegian Sea is important for the climate in these regions. A better understanding of the climate variability on highly resolved time scales is needed to obtain a better fundament for climate predictions for these areas. However, highly resolved paleoclimate records are sparse in the North Atlantic and instrumental data cover only the last 50 - 150 years. Bivalve shells provide highly resolved climate archives, especially the shells of the long-lived bivalve species Arctica islandica. This widely occurring species forms annual growth increments, which can be analyzed similarly to tree rings. Climatic and oceanographic changes are recorded population-wide in the shell`s growth rate and in the isotopic composition of the shell. Hence, multi-centennial absolutely dated chronologies can be built by cross-matching live-collected and sub-fossil specimens. Our chronology building effort has led to the first multi-centennial absolutely dated chronology from the Faroese Shelf covering the time period from AD 1642 - 2013. The growth indices of the chronology anti-correlate with April - September sea surface temperatures (SST) for the last 100 years indicating favorable conditions for growth when temperatures are lower. This also suggests that the main growing season of A. islandica around the Faroe Islands occurs in this time period; a hypothesis supported by δ18O-based temperature reconstructions from growth increments representing the years 2001 - 2013. The RBAR, which is an indicator for the signal strength throughout the chronology shows an inverse relationship with Atlantic Multi-decadal Oscillation (AMO) data indicating that periods of higher AMO indexes result in a weakened signal strength in the chronology for the same time period. In conclusion, our results

  16. 50 CFR 648.15 - Facilitation of enforcement.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... ocean quahog open access permitted vessels. Vessel owners or operators issued an open access surfclam or ocean quahog open access permit for fishing in the ITQ Program, as specified at § 648.70, are required... limited access permitted vessels. Beginning January 1, 2009, vessel owners or operators issued a limited...

  17. 50 CFR 648.73 - Closed areas.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... ocean quahog Accountability Measures. (a) Commercial ITQ fishery. (1) If the ACL for surfclam or ocean.... (2) Any amount of an ACL overage that cannot be otherwise attributed to an ITQ allocation holder will be deducted from the appropriate ACL in the following fishing year. (b) Maine mahogany quahog fishery...

  18. Shell architecture: a novel proxy for paleotemperature reconstructions?

    NASA Astrophysics Data System (ADS)

    Milano, Stefania; Nehrke, Gernot; Wanamaker, Alan D., Jr.; Witbaard, Rob; Schöne, Bernd R.

    2017-04-01

    Mollusk shells are unique high-resolution paleoenvironmental archives. Their geochemical properties, such as oxygen isotope composition (δ18Oshell) and element-to-calcium ratios, are routinely used to estimate past environmental conditions. However, the existing proxies have certain drawbacks that can affect paleoreconstruction robustness. For instance, the estimation of water temperature of brackish and near-shore environments can be biased by the interdependency of δ18Oshell from multiple environmental variables (water temperature and δ18Owater). Likely, the environmental signature can be masked by physiological processes responsible for the incorporation of trace elements into the shell. The present study evaluated the use of shell structural properties as alternative environmental proxies. The sensitivity of shell architecture at µm and nm-scale to the environment was tested. In particular, the relationship between water temperature and microstructure formation was investigated. To enable the detection of potential structural changes, the shells of the marine bivalves Cerastoderma edule and Arctica islandica were analyzed with Scanning Electron Microscopy (SEM), nanoindentation and Confocal Raman Microscopy (CRM). These techniques allow a quantitative approach to the microstructural analysis. Our results show that water temperature induces a clear response in shell microstructure. A significant alteration in the morphometric characteristics and crystallographic orientation of the structural units was observed. Our pilot study suggests that shell architecture records environmental information and it has potential to be used as novel temperature proxy in near-shore and open ocean habitats.

  19. 50 CFR 648.74 - Shucking at sea.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 50 Wildlife and Fisheries 8 2010-10-01 2010-10-01 false Shucking at sea. 648.74 Section 648.74... Clam and Ocean Quahog Fisheries § 648.74 Shucking at sea. (a) Observers. (1) The Regional Administrator may allow the shucking of surf clams or ocean quahogs at sea if he/she determines that an observer...

  20. 50 CFR 648.74 - Shucking at sea.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 10 2011-10-01 2011-10-01 false Shucking at sea. 648.74 Section 648.74... Clam and Ocean Quahog Fisheries § 648.74 Shucking at sea. Link to an amendment published at 76 FR 60623... ocean quahogs at sea if he/she determines that an observer carried aboard the vessel can measure...

  1. Sclerochronology - tool for uncovering environmental drivers in a semi-enclosed sea

    NASA Astrophysics Data System (ADS)

    Vilibic, I.; Peharda, M.; Dzoic, T.; Markulin, K.; Dunic, N.; Mihanovic, H.; Gacic, M.; Black, B.; Uvanovic, H.; Ezgeta-Balic, D.; Sepic, J.; Kovac, Z.; Zupan, I.

    2017-12-01

    A number of proxy-based methods have been developed in detection of long-term environmental changes. Among them is sclerochronology which, through analysis of inter annular variations in widths of growth increments, has been advancing in recent decades. Albeit the main focus has been directed towards species living over centuries and in cold seas (primarily Arctica islandica), application of sclerochronology in temperate seas has potential to contribute toward better understanding of physical and environmental properties and processes in semi-enclosed seas. Here, we are presenting the major results of the project SCOOL (Sclerochronology as a tool for detecting long-term Adriatic environmental changes, http://www.izor.hr/web/scool), aiming to relate relatively long-lived bivalve species Glycymeris pilosa to the major environmental drivers in a semi-enclosed sea of the Mediterranean, the Adriatic Sea. The open Adriatic Sea is known to be dominated by quasi-decadal oscillations in thermohaline and biogeochemical properties driven by the dense water formation, so a question has been posed to quantify its role in driving the bivalve growth with respect to other environmental drivers (like heat fluxes, river discharges, precipitation). It seems that these basin-wide oscillations are dominating over locally-driven processes, even in coastal regions that include very shallow northern Adriatic. The northern Adriatic has been previously considered as quasi-separated from the basin-wide dynamics; such conclusions have been reached from multi-decadal in situ sampling series of different physical and chemical parameters. Therefore, sclerochronology is documented to be a reliable tool for detection of environmental drivers in a coastal temperate sea.

  2. Biological and Climate Controls on North Atlantic Marine Carbon Dynamics Over the Last Millennium: Insights From an Absolutely Dated Shell-Based Record From the North Icelandic Shelf

    NASA Astrophysics Data System (ADS)

    Reynolds, D. J.; Hall, I. R.; Scourse, J. D.; Richardson, C. A.; Wanamaker, A. D.; Butler, P. G.

    2017-12-01

    Given the rapid increase in atmospheric carbon dioxide concentrations (pCO2) over the industrial era, there is a pressing need to construct long-term records of natural carbon cycling prior to this perturbation and to develop a more robust understanding of the role the oceans play in the sequestration of atmospheric carbon. Here we reconstruct the past biological and climate controls on the carbon isotopic (δ13Cshell) composition of the North Icelandic shelf waters over the last millennium, derived from the shells of the long-lived marine bivalve mollusk Arctica islandica. Variability in the annually resolved δ13Cshell record is dominated by multidecadal variability with a negative trend (-0.003 ± 0.002‰ yr-1) over the industrial era (1800-2000 Common Era). This trend is consistent with the marine Suess effect brought about by the sequestration of isotopically light carbon (δ13C of CO2) derived from the burning of fossil fuels. Comparison of the δ13Cshell record with Contemporaneous proxy archives, over the last millennium, and instrumental data over the twentieth century, highlights that both biological (primary production) and physical environmental factors, such as relative shifts in the proportion of Subpolar Mode Waters and Arctic Intermediate Waters entrained onto the North Icelandic shelf, atmospheric circulation patterns associated with the winter North Atlantic Oscillation, and sea surface temperature and salinity of the subpolar gyre, are the likely mechanisms that contribute to natural variations in seawater δ13C variability on the North Icelandic shelf. Contrasting δ13C fractionation processes associated with these biological and physical mechanisms likely cause the attenuated marine Suess effect signal at this locality.

  3. Biological and climate controls on North Atlantic marine carbon dynamics over the last millennium: Insights from an absolutely-dated shell based record from the North Icelandic Shelf

    NASA Astrophysics Data System (ADS)

    Hall, I. R.; Reynolds, D.; Scourse, J. D.; Richardson, C.; Wanamaker, A. D.; Butler, P. G.

    2017-12-01

    Given the rapid increase in atmospheric carbon dioxide concentrations (pCO2) over the industrial era there is a pressing need to construct longterm records of natural carbon cycling prior to this perturbation and to develop a more robust understanding of the role the oceans play in the sequestration of atmospheric carbon. Here we reconstruct the historical biological and climatic controls on the carbon isotopic (δ13C-shell) composition of the North Icelandic shelf waters over the last millennium derived from the shells of the long-lived marine bivalve mollusc Arctica islandica. Variability in the annually resolved δ13C-shell record is dominated by multi-decadal variability with a negative trend (-0.003±0.002‰yr-1) over the industrial era (1800-2000). This trend is consistent with the marine Suess effect brought about by the sequestration of isotopically light carbon (δ13C of CO2) derived from the burning of fossil fuels. Comparison of the δ13C-shell record with contemporary proxy archives, over the last millennium, and instrumental data over the 20th century, suggests that primary productivity and climate conditions over the sub-polar North Atlantic region played a vital role in driving inter-annual to multi-decadal scale variability in the δ13C-shell record. Our results highlight that relative shifts in the proportion of sub-polar mode waters and Arctic intermediate waters entrained onto the North Icelandic shelf, coupled with atmospheric circulation patterns associated with the winter North Atlantic Oscillation (wNAO), are the likely physical mechanisms that drive natural variations in seawater δ13C variability on the North Icelandic shelf.

  4. An annually resolved marine proxy record for the 8.2K cold event from the northern North Sea based on bivalve shells

    NASA Astrophysics Data System (ADS)

    Butler, Paul; Estrella-Martínez, Juan; Scourse, James

    2017-04-01

    The so-called 8.2K cold event is a rapid cooling of about 6° +/- 2° recorded in the Greenland ice core record and thought to be a consequence of a freshwater pulse from the Laurentide ice sheet which reduced deepwater formation in the North Atlantic. In the Greenland ice cores the event is characterized by a maximum extent of 159 years and a central event lasting for 70 years. As discussed by Thomas et al (QSR, 2007), the low resolution and dating uncertainty of much palaeoclimate data makes it difficult to determine the rates of change and causal sequence that characterise the event at different locations. We present here a bivalve shell chronology based on four shells of Arctica islandica from the northern North Sea which (within radiocarbon uncertainty) is coeval with the 8.2K event recorded in the Greenland ice cores. The years of death of each shell based on radiocarbon analysis and crossmatching are 8094, 8134, 8147, and 8208 yrs BP (where "present" = AD 1950), with an associated radiocarbon uncertainty of +/-80 yrs, and their longevities are 106, 122, 112 and 79 years respectively. The total length of the chronology is 192 years (8286 - 8094 BP +/- 80 yrs). The most noticeable feature of the chronology is an 60-year period of increasing growth which may correspond to a similar period of decreasing ice accumulation in the GRIP (central Greenland) ice core record. We tentatively suggest that this reflects increasing food supply to the benthos as summer stratification is weakened by colder seawater temperatures. Stable isotope analyses (results expected to be available when this abstract is presented), will show changes at annual and seasonal resolution, potentially giving a very detailed insight into the causal factors associated with the 8.2K event and its impact in the northern North Sea.

  5. Quantification of diagenetic overprint processes deduced from fossil carbonate shells and laboratory-based hydrothermal alteration experiments

    NASA Astrophysics Data System (ADS)

    Griesshaber, Erika; Casella, Laura; Mavromatis, Vasileios; Dietzel, Martin; Immenhauser, Adrian; Schmahl, Wolfgang

    2016-04-01

    Benthic and nektonic marine biogenic carbonate archives represent the foundation of numerous studies aiming at reconstructions of past climate dynamics and environmental change. However, living organisms are not in thermodynamic equilibrium and create local chemical environments where physiologic processes such as biomineralization takes place. After the death of the organism the former physiologic disequilibrium conditions are not sustained any more and all biological tissues are altered by equilibration according to the surrounding environment: diagenesis. With increasing diagenetic alteration, the biogenic structure and fingerprint fades away and is replaced by inorganic features. Thus, recrystallization of organism-specific microstructure is a clear indicator for diagenetic overprint. Microstructural data, which mirror recrystallization, are of great value for interpreting geochemical proxies for paleo-environment reconstruction. Despite more than a century of research dealing with carbonate diagenesis, many of the controlling processes and factors are only understood in a qualitative manner. One of the main issues is that diagenetically altered carbonates are usually present as the product of a complex preceding diagenetic pathway with an unknown number of intermediate steps. In this contribution we present and discuss laboratory based alteration experiments with the aim to investigate time-series data sets in a controlled manner. We conducted hydrothermal alteration experiments with modern Arctica islandica (bivalvia) and Notosaria nigricans (brachiopoda) in order to mimic diagenetic overprint. We explore first the potential of electron backscattered diffraction (EBSD) measurements together with statistical data evaluation as a tool to quantify diagenetic alteration of carbonate skeletons. Subsequently, we compare microstructural patterns obtained from experimentally altered shell material with those of fossil specimens that have undergone variable degrees of

  6. 50 CFR 648.1 - Purpose and scope.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ..., and butterfish fisheries (Atlantic Mackerel, Squid, and Butterfish FMP); Atlantic salmon (Atlantic Salmon FMP); the Atlantic sea scallop fishery (Scallop FMP); the Atlantic surf clam and ocean quahog...

  7. 50 CFR 648.6 - Dealer/processor permits.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... surfclam, ocean quahog, Atlantic mackerel, squid, butterfish, scup, bluefish, tilefish, and black sea bass... the fishing year to an applicant, unless the applicant fails to submit a completed application. An...

  8. 50 CFR 648.6 - Dealer/processor permits.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... surfclam, ocean quahog, Atlantic mackerel, squid, butterfish, scup, bluefish, tilefish, and black sea bass... the fishing year to an applicant, unless the applicant fails to submit a completed application. An...

  9. 50 CFR 648.75 - Cage identification.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ..., DEPARTMENT OF COMMERCE FISHERIES OF THE NORTHEASTERN UNITED STATES Management Measures for the Atlantic Surf... clams and ocean quahogs: (a) Tagging. Before offloading, all cages that contain surfclams or ocean...

  10. 50 CFR 648.73 - Closed areas.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... degradation. Certain areas are closed to all surf clam and ocean quahog fishing because of adverse... safe for human consumption. For information regarding these areas contact the State of Maine Division...

  11. 78 FR 57620 - Mid-Atlantic Fishery Management Council (MAFMC); Public Meetings

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-19

    ... Project. The Council will hold a public Listening Session with a presentation on Ocean Acidification. On... Reports to include an update on forms and process for data collection for the surfclam and ocean quahog...

  12. Crystal structure of a cold-active protease (Pro21717) from the psychrophilic bacterium, Pseudoalteromonas arctica PAMC 21717, at 1.4 Å resolution: Structural adaptations to cold and functional analysis of a laundry detergent enzyme.

    PubMed

    Park, Ha Ju; Lee, Chang Woo; Kim, Dockyu; Do, Hackwon; Han, Se Jong; Kim, Jung Eun; Koo, Bon-Hun; Lee, Jun Hyuck; Yim, Joung Han

    2018-01-01

    Enzymes isolated from organisms found in cold habitats generally exhibit higher catalytic activity at low temperatures than their mesophilic homologs and are therefore known as cold-active enzymes. Cold-active proteases are very useful in a variety of biotechnological applications, particularly as active ingredients in laundry and dishwashing detergents, where they provide strong protein-degrading activity in cold water. We identified a cold-active protease (Pro21717) from a psychrophilic bacterium, Pseudoalteromonas arctica PAMC 21717, and determined the crystal structure of its catalytic domain (CD) at a resolution of 1.4 Å. The Pro21717-CD structure shows a conserved subtilisin-like fold with a typical catalytic triad (Asp185, His244, and Ser425) and contains four calcium ions and three disulfide bonds. Interestingly, we observed an unexpected electron density at the substrate-binding site from a co-purified peptide. Although the sequence of this peptide is unknown, analysis of the peptide-complexed structure nonetheless provides some indication of the substrate recognition and binding mode of Pro21717. Moreover, various parameters, including a wide substrate pocket size, an abundant active-site loop content, and a flexible structure provide potential explanations for the cold-adapted properties of Pro21717. In conclusion, this is first structural characterization of a cold-adapted subtilisin-like protease, and these findings provide a structural and functional basis for industrial applications of Pro21717 as a cold-active laundry or dishwashing detergent enzyme.

  13. Crystal structure of a cold-active protease (Pro21717) from the psychrophilic bacterium, Pseudoalteromonas arctica PAMC 21717, at 1.4 Å resolution: Structural adaptations to cold and functional analysis of a laundry detergent enzyme

    PubMed Central

    Do, Hackwon; Han, Se Jong; Kim, Jung Eun; Koo, Bon-Hun; Yim, Joung Han

    2018-01-01

    Enzymes isolated from organisms found in cold habitats generally exhibit higher catalytic activity at low temperatures than their mesophilic homologs and are therefore known as cold-active enzymes. Cold-active proteases are very useful in a variety of biotechnological applications, particularly as active ingredients in laundry and dishwashing detergents, where they provide strong protein-degrading activity in cold water. We identified a cold-active protease (Pro21717) from a psychrophilic bacterium, Pseudoalteromonas arctica PAMC 21717, and determined the crystal structure of its catalytic domain (CD) at a resolution of 1.4 Å. The Pro21717-CD structure shows a conserved subtilisin-like fold with a typical catalytic triad (Asp185, His244, and Ser425) and contains four calcium ions and three disulfide bonds. Interestingly, we observed an unexpected electron density at the substrate-binding site from a co-purified peptide. Although the sequence of this peptide is unknown, analysis of the peptide-complexed structure nonetheless provides some indication of the substrate recognition and binding mode of Pro21717. Moreover, various parameters, including a wide substrate pocket size, an abundant active-site loop content, and a flexible structure provide potential explanations for the cold-adapted properties of Pro21717. In conclusion, this is first structural characterization of a cold-adapted subtilisin-like protease, and these findings provide a structural and functional basis for industrial applications of Pro21717 as a cold-active laundry or dishwashing detergent enzyme. PMID:29466378

  14. 50 CFR 648.71 - Catch quotas.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Maine and non-Maine ocean quahog ACTs shall be less than or equal to the ACL for the corresponding stock... relative to ACTs in conjunction with any ACL performance review, as outlined in § 648.70(b)(1) through (3). ...

  15. Arbuscular mycorrhizas are present on Spitsbergen.

    PubMed

    Newsham, K K; Eidesen, P B; Davey, M L; Axelsen, J; Courtecuisse, E; Flintrop, C; Johansson, A G; Kiepert, M; Larsen, S E; Lorberau, K E; Maurset, M; McQuilkin, J; Misiak, M; Pop, A; Thompson, S; Read, D J

    2017-10-01

    A previous study of 76 plant species on Spitsbergen in the High Arctic concluded that structures resembling arbuscular mycorrhizas were absent from roots. Here, we report a survey examining the roots of 13 grass and forb species collected from 12 sites on the island for arbuscular mycorrhizal (AM) colonisation. Of the 102 individuals collected, we recorded AM endophytes in the roots of 41 plants of 11 species (Alopecurus ovatus, Deschampsia alpina, Festuca rubra ssp. richardsonii, putative viviparous hybrids of Poa arctica and Poa pratensis, Poa arctica ssp. arctica, Trisetum spicatum, Coptidium spitsbergense, Ranunculus nivalis, Ranunculus pygmaeus, Ranunculus sulphureus and Taraxacum arcticum) sampled from 10 sites. Both coarse AM endophyte, with hyphae of 5-10 μm width, vesicles and occasional arbuscules, and fine endophyte, consisting of hyphae of 1-3 μm width and sparse arbuscules, were recorded in roots. Coarse AM hyphae, vesicles, arbuscules and fine endophyte hyphae occupied 1.0-30.7, 0.8-18.3, 0.7-11.9 and 0.7-12.8% of the root lengths of colonised plants, respectively. Principal component analysis indicated no associations between the abundances of AM structures in roots and edaphic factors. We conclude that the AM symbiosis is present in grass and forb roots on Spitsbergen.

  16. 76 FR 72125 - Magnuson-Stevens Fishery Conservation and Management Act Provisions; Fisheries of the...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-22

    ... harvest of Atlantic surfclams, ocean quahogs, and sea scallop adductor muscles harvested and shucked at... below. Under this emergency rule, this area remains closed to the harvest of Atlantic surfclams, ocean... attempt to fish for, harvest, catch, or possess any bivalve shellfish, including Atlantic surfclams, ocean...

  17. 50 CFR 648.1 - Purpose and scope.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... fishery (Scallop FMP); the Atlantic surf clam and ocean quahog fisheries (Atlantic Surf Clam and Ocean... clam” and “Surf Clam” and adding “surfclam” and “Surfclam” in their place, respectively, effective... fishery management plans (FMPs) for the Atlantic mackerel, squid, and butterfish fisheries (Atlantic...

  18. 75 FR 76351 - Magnuson-Stevens Fishery Conservation and Management Act Provisions; Fisheries of the...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-08

    ... that accumulate in water column filter- feeding shellfish. Shellfish contaminated with the toxin, if... to collect water and shellfish samples from Federal waters off of southern New England. The FDA, in... ocean quahogs for human consumption. The FDA indicated that testing of clams from the portion of the GB...

  19. 50 CFR 648.7 - Recordkeeping and reporting requirements.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...; date(s) of purchases and receipts; units of measure and amount by species (by market category, if applicable); price per unit by species (by market category, if applicable) or total value by species (by market category, if applicable); port landed; cage tag numbers for surfclams and ocean quahogs, if...

  20. 50 CFR 648.7 - Recordkeeping and reporting requirements.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...; date(s) of purchases and receipts; units of measure and amount by species (by market category, if applicable); price per unit by species (by market category, if applicable) or total value by species (by market category, if applicable); port landed; cage tag numbers for surfclams and ocean quahogs, if...

  1. 50 CFR 648.7 - Recordkeeping and reporting requirements.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...; date(s) of purchases and receipts; units of measure and amount by species (by market category, if applicable); price per unit by species (by market category, if applicable) or total value by species (by market category, if applicable); port landed; cage tag numbers for surfclams and ocean quahogs, if...

  2. 50 CFR 648.7 - Recordkeeping and reporting requirements.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...; date(s) of purchases and receipts; units of measure and amount by species (by market category, if applicable); price per unit by species (by market category, if applicable) or total value by species (by market category, if applicable); port landed; cage tag numbers for surfclams and ocean quahogs, if...

  3. 50 CFR 648.71 - Catch quotas.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... specification will be based on the most recent available survey and stock assessments for Atlantic surfclams and..., DEPARTMENT OF COMMERCE FISHERIES OF THE NORTHEASTERN UNITED STATES Management Measures for the Atlantic Surf... amount of surfclams or ocean quahogs that may be caught annually by fishing vessels subject to these...

  4. 77 FR 4013 - Mid-Atlantic Fishery Management Council (MAFMC); Public Meetings

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-26

    ... Committee, its Ecosystem and Ocean Planning Committee, and its Spiny Dogfish Committee will hold public...--The Surfclam, Ocean Quahog and Tilefish Committee will meet from 1 p.m. until 3 p.m. The Ecosystem and... discuss and identify the next steps for Amendment 15. The Ecosystem and Ocean Planning Committee will...

  5. 50 CFR 697.6 - Dealer permits.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... requirement; date(s) of purchases and receipts; units of measure and amount by species (by market category, if applicable); price per unit by species (by market category, if applicable) or total value by species (by market category, if applicable); port landed; cage tag numbers for surfclams and ocean quahogs, if...

  6. 50 CFR 697.6 - Dealer permits.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... requirement; date(s) of purchases and receipts; units of measure and amount by species (by market category, if applicable); price per unit by species (by market category, if applicable) or total value by species (by market category, if applicable); port landed; cage tag numbers for surfclams and ocean quahogs, if...

  7. 50 CFR 697.6 - Dealer permits.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... requirement; date(s) of purchases and receipts; units of measure and amount by species (by market category, if applicable); price per unit by species (by market category, if applicable) or total value by species (by market category, if applicable); port landed; cage tag numbers for surfclams and ocean quahogs, if...

  8. 76 FR 65698 - Magnuson-Stevens Act Provisions; General Provisions for Domestic Fisheries; Application for...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-24

    ... Atlantic surfclam and ocean quahog Georges Bank Closure Area to continue testing the safety and efficacy of... research project that has been ongoing since 2006. NMS has made a preliminary determination that the...: http://www.nero.noaa.gov/sfd/clams . This project is a pilot program with the goal of determining if...

  9. In the darkness of the polar night, scallops keep on a steady rhythm

    NASA Astrophysics Data System (ADS)

    Tran, Damien; Sow, Mohamedou; Camus, Lionel; Ciret, Pierre; Berge, Jorgen; Massabuau, Jean-Charles

    2016-08-01

    Although the prevailing paradigm has held that the polar night is a period of biological quiescence, recent studies have detected noticeable activity levels in marine organisms. In this study, we investigated the circadian rhythm of the scallop Chlamys islandica by continuously recording the animal’s behaviour over 3 years in the Arctic (Svalbard). Our results showed that a circadian rhythm persists throughout the polar night and lasts for at least 4 months. Based on observations across three polar nights, we showed that the robustness and synchronicity of the rhythm depends on the angle of the sun below the horizon. The weakest rhythm occurred at the onset of the polar night during the nautical twilight. Surprisingly, the circadian behaviour began to recover during the darkest part of the polar night. Because active rhythms optimize the fitness of an organism, our study brings out that the scallops C. islandica remain active even during the polar night.

  10. Enzymatic and cellular responses in relation to body burden of PAHs in bivalve molluscs: a case study with chronic levels of North Sea and Barents Sea dispersed oil.

    PubMed

    Baussant, T; Bechmann, R K; Taban, I C; Larsen, B K; Tandberg, A H; Bjørnstad, A; Torgrimsen, S; Naevdal, A; Øysaed, K B; Jonsson, G; Sanni, S

    2009-12-01

    Mytilus edulis and Chlamys islandica were exposed to nominal dispersed crude oil concentrations in the range 0.015-0.25 mg/l for one month. Five biomarkers (enzymatic and cellular responses) were analysed together with bioaccumulation of PAHs at the end of exposure. In both species, PAH tissue residues reflected the exposure concentration measured in the water and lipophilicity determined the bioaccumulation levels. Oil caused biomarker responses in both species but more significant alterations in exposed C. islandica were observed. The relationships between exposure levels and enzymatic responses were apparently complex. The integrated biomarker response related against the exposure levels was U-shaped in both species and no correlation with total PAH body burden was found. For the monitoring of chronic offshore discharges, dose- and time-related events should be evaluated in the selection of biomarkers to apply. From this study, cellular damages appear more fitted than enzymatic responses, transient and more complex to interpret.

  11. 50 CFR 648.75 - Shucking at sea and minimum surfclam size.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 50 Wildlife and Fisheries 12 2012-10-01 2012-10-01 false Shucking at sea and minimum surfclam size... Measures for the Atlantic Surf Clam and Ocean Quahog Fisheries § 648.75 Shucking at sea and minimum surfclam size. (a) Shucking at sea—(1) Observers. (i) The Regional Administrator may allow the shucking of...

  12. 50 CFR 648.75 - Shucking at sea and minimum surfclam size.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 12 2014-10-01 2014-10-01 false Shucking at sea and minimum surfclam size... Measures for the Atlantic Surf Clam and Ocean Quahog Fisheries § 648.75 Shucking at sea and minimum surfclam size. (a) Shucking at sea—(1) Observers. (i) The Regional Administrator may allow the shucking of...

  13. 50 CFR 648.75 - Shucking at sea and minimum surfclam size.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 12 2013-10-01 2013-10-01 false Shucking at sea and minimum surfclam size... Measures for the Atlantic Surf Clam and Ocean Quahog Fisheries § 648.75 Shucking at sea and minimum surfclam size. (a) Shucking at sea—(1) Observers. (i) The Regional Administrator may allow the shucking of...

  14. Nitrogen extraction potential of wild and cultured bivalves harvested from nearshore waters of Cape Cod, USA.

    PubMed

    Reitsma, Joshua; Murphy, Diane C; Archer, Abigail F; York, Richard H

    2017-03-15

    As nitrogen entering coastal waters continues to be an issue, much attention has been generated to identify potential options that may help alleviate this stressor to estuaries, including the propagation of bivalves to remove excess nitrogen. Oysters (Crassostrea virginica) and quahogs (Mercenaria mercenaria) from numerous Cape Cod, MA, (USA) sources were analyzed for nitrogen content stored in tissues that would represent a net removal of nitrogen from a water body if harvested. Results showed local oysters average 0.69% nitrogen by total dry weight (mean 0.28gN/animal) and quahogs average 0.67% nitrogen by total dry weight (mean 0.22gN/animal); however, these values did vary by season and to a lesser extent by location or grow-out method. The differences in nitrogen content were largely related to the mass of shell or soft tissue. Nitrogen isotope data indicate shellfish from certain water bodies in the region are incorporating significant amounts of nitrogen from anthropogenic sources. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  15. 50 CFR 648.81 - NE multispecies closed areas and measures to protect EFH.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... designed and used to take surfclams or ocean quahogs, provided that there is no retention of regulated...′ 70°00′ 1 Cape Cod shoreline on the Atlantic Ocean. (ii) Rolling Closure Area II. From April 1 through... Cape Cod Bay. 3 Cape Cod shoreline on the Atlantic Ocean. 4 New Hampshire shoreline. (iii) Rolling...

  16. 50 CFR 648.81 - NE multispecies closed areas and measures to protect EFH.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... designed and used to take surfclams or ocean quahogs, provided that there is no retention of regulated...′ 70°00′ 1 Cape Cod shoreline on the Atlantic Ocean. (ii) Rolling Closure Area II. From April 1 through... Cape Cod Bay. 3 Cape Cod shoreline on the Atlantic Ocean. 4 New Hampshire shoreline. (iii) Rolling...

  17. 50 CFR 648.81 - NE multispecies closed areas and measures to protect EFH.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... designed and used to take surfclams or ocean quahogs, provided that there is no retention of regulated...′ 70°00′ 1 Cape Cod shoreline on the Atlantic Ocean. (ii) Rolling Closure Area II. From April 1 through... Cape Cod Bay. 3 Cape Cod shoreline on the Atlantic Ocean. 4 New Hampshire shoreline. (iii) Rolling...

  18. 50 CFR 648.72 - Minimum surf clam size.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Atlantic Surf Clam and Ocean Quahog Fisheries § 648.72 Minimum surf clam size. (a) Minimum length. The minimum length for surf clams is 4.75 inches (12.065 cm). (b) Determination of compliance. No more than 50... 50 Wildlife and Fisheries 8 2010-10-01 2010-10-01 false Minimum surf clam size. 648.72 Section 648...

  19. 75 FR 65442 - Magnuson-Stevens Fishery Conservation and Management Act Provisions; Fisheries of the...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-25

    ... increase in biomass and recruitment on Georges Bank and off Long Island, NY. Based on this information, the..., stock recruitment, projected fishing effort and catches, and areas closed to fishing. In June 2010, the... Quahogs \\3\\ 100,000 35,240 100,000 35,240 100,000 35,240 \\1\\ Numerical values are in millions except for...

  20. Leaf Mass Area, Leaf Carbon and Nitrogen Content, Barrow, Alaska, 2012-2016

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Rogers, Alistair; Ely, Kim; Serbin, Shawn

    Carbon, Nitrogen and Leaf Mass Area of leaves sampled from the Barrow Environmental Observatory, Barrow, Alaska. Species measured; Arctophila fulva, Arctagrostis latifolia, Carex aquatilis, Dupontia fisheri, Eriophorum angustifolium, Petasites frigidus, Salix pulchra, Vaccinium vitis-idaea, Salix rotundifolia, Luzula arctica, Saxifraga punctata and Potentilla hyparctica.

  1. A Climatological Oil Spill Planning Guide. Number 2. Gulf of Maine/Georges Bank,

    DTIC Science & Technology

    1981-06-01

    95 73 Shellfish Distribution: Surf clams and soft clams . . . . . 97 74 Shellfish Distribution: Ocean Quahogs and hard clams . . . . 98 75...have been included in the analysis. - 96 - 716 709 69’ No’ 670 No’ ILI Surf Clam Distribution ..... 45’ * Soft Clam Majo Concontraitln45 44 44’ N..w...18 7 Prevailing winter and summer pressure patterns in the North Atlantic . . . . . . .. .. . . . . . . . . . . . . . . 24 8 Storm tracks, winter

  2. Sub-Ice Microalgal and Bacterial Communities in Freshwater Lake Baikal, Russia.

    PubMed

    Bashenkhaeva, Maria V; Zakharova, Yulia R; Petrova, Darya P; Khanaev, Igor V; Galachyants, Yuri P; Likhoshway, Yelena V

    2015-10-01

    The sub-ice environment of Lake Baikal represents a special ecotope where strongly increasing microbial biomass causes an "ice-bloom" contributing therefore to the ecosystem functioning and global element turnover under low temperature in the world's largest freshwater lake. In this work, we analyzed bacterial and microalgal communities and their succession in the sub-ice environment in March-April 2010-2012. It was found out that two dinoflagellate species (Gymnodinium baicalense var. minor and Peridinium baicalense Kisselew et Zwetkow) and four diatom species (Aulacoseira islandica, A. baicalensis, Synedra acus subsp. radians, and Synedra ulna) predominated in the microalgal communities. Interestingly, among all microalgae, the diatom A. islandica showed the highest number of physically attached bacterial cells (up to 67 ± 16 bacteria per alga). Bacterial communities analyzed with pyrosequencing of 16S rRNA gene fragments were diverse and represented by 161 genera. Phyla Proteobacteria, Verrucomicrobia, Actinobacteria, Acidobacteria, Bacteroidetes, and Cyanobacteria represented a core community independently on microalgal composition, although the relative abundance of these bacterial phyla strongly varied across sampling sites and time points; unique OTUs from other groups were rare.

  3. Risk of Pore Water Hydrogen Sulfide Toxicity in Dredged Material Bioassays

    DTIC Science & Technology

    1995-11-01

    Prog. Ser. 101, 147-155. Moore, D. W., and Dillon, T. M. (1993). “Chronic sublethal effects of San Francisco Bay sediments on Neris (Neanthes...metabolism of Arctica isfandica L. (Bivalvia),” J. Exp. Mar. Biol. Ecol. 170, 213-226. Oritz, J. A., Rueda, A., Carbonell, G., Camargo , J. A., Nieto, F

  4. Sr/Ca and Mg/Ca in Glycymeris glycymeris (Bivalvia) shells from the Iberian upwelling system: Ontogeny and environmental control

    NASA Astrophysics Data System (ADS)

    Freitas, Pedro; Richardson, Christopher; Chenery, Simon; Monteiro, Carlos; Butler, Paul; Reynolds, David; Scourse, James; Gaspar, Miguel

    2017-04-01

    Bivalve shells have a great potential as high-resolution geochemical proxy archives of marine environmental conditions. In addition, sclerochronology of long-lived bivalve species (e.g. Arctica islandica) provides a timeline of absolutely dated shell material for geochemical analysis that can extend into the past beyond the lifetime of single individuals through the use of replicated crossmatched centennial to millennial chronologies. However, the interpretation of such records remains extremely challenging and complex, with multiple environmental and biological processes affecting element incorporation in the shell (e.g. crystal fabrics, organic matrix, biomineralization mechanisms and physiological processes). As a result, the effective use of bivalve shell elemental/Ca ratios as palaeoenvironmental proxies has been limited, often to species-specific applications or applications restricted to particular environmental settings. The dog-cockle, Glycymeris glycymeris, is a relatively long-lived bivalve (up to 200 years) that occurs in coarse-grained subtidal sediments of coastal shelf seas of Europe and North West Africa. Glycymeris glycymeris shells provide a valuable, albeit not fully explored, archive to reconstruct past environmental variability in an area lacking sclerochronological studies due to the rarity of long-lived bivalves and lack of coral reefs. In this study, we evaluate the potential of Sr/Ca and Mg/Ca ratios in G. glycymeris shells as geochemical proxies of upwelling conditions in the Iberian Upwelling System, the northern section of the Canary Current Eastern Boundary Upwelling System. Sr/Ca and Mg/Ca generally co-varied significantly and a clear ontogenetic, non-environmental related change in Sr/Ca and Ba/Ca variability was observed. High Sr/Ca and Mg/Ca ratios in older shells (> 10 years old) were found to be associated with the occurrence of growth lines deposited during the winter reduction in shell growth. Nevertheless, Sr/Ca and Mg

  5. How Vulnerable is Perennial Sea Ice? Insights from Earth's Late Cenozoic Natural Experiments (Invited)

    NASA Astrophysics Data System (ADS)

    Brigham-Grette, J.; Polyak, L. V.; Caissie, B.; Sharko, C. J.; Petsch, S.

    2010-12-01

    Sea ice is an important component of the climate system. Yet, reconstructions of Arctic sea ice conditions reflecting glacial and interglacial change over the past 3 million years are almost nonexistent. Our work to evaluate the sea ice and sea surface temperature record of the Bering Strait region builds on a review of the sea ice history of the pan-Arctic. The best estimates of sea ice make use of indirect proxies based on reconstructions of treeline, sea surface temperatures, depositional systems, and the ecological preferences of extant marine microfossil species. The development of new proxies of past sea ice extent including microfossil assemblages (diatoms, ostracodes) and biomarker proxies (IP25) show promise for quantifying seasonal concentrations of sea ice cover on centennial to millennial timescales. Using both marine and terrestrial information, periods of restricted sea ice and ice-free Arctic conditions can be inferred for parts of the late Cenozoic. The Arctic Ocean borderlands contain clear stratigraphic evidence for forested conditions at intervals over the past 50 million years, recording the migration of treeline from High Arctic coastal locations within the Canadian Archipelago. Metasequoia forests of the peak Eocene gave way to a variety of biomass-rich circumarctic redwood forests by 46 Ma. Between 23 and 16 Ma, cool-temperate metasequoia forests dominated NE Alaska and the Yukon while mixed conifer-hardwood forests (similar to those of modern southern maritime Canada and New England) dominated the central Canadian Archipelago. By 16 Ma, these forests gave way to larch and spruce. From 5 to 3 Ma the braid plains of the Beaufort Fm were dominated by over 100 vascular plants including pine and birch, while other locations remained dominated by spruce and larch. Boreal conditions across northern Greenland and arctic Alaska are consistent with the presence of bivalve Arctica islandica in marine sediments capping the Beaufort Formation on Meighen

  6. Plant Functional Traits Are More Consistent Than Plant Species on Periglacial Patterned Ground in the Rocky Mountains of Montana

    NASA Astrophysics Data System (ADS)

    Apple, M. E.; Ricketts, M. K.; Gallagher, J. H. R.

    2017-12-01

    Periglacial patterned ground exists as stripes and hexagons near glaciers and snowfields, some of which are former glaciers. The patterns are accentuated by profound differences in plant cover between the sloping surfaces, generally perceived as green, and the flat treads, generally perceived as brown but which are not devoid of plant life. On four sites in the Rocky Mountains of Montana we detected strong similarities in plant functional traits on the sloping surfaces of striped and hexagonal periglacial patterned ground. On Mt. Keokirk in the Pioneer Mountains, Kinnickinnick, Arctostaphylos uva-ursi, dominates narrow green stripes. On Goat Flat in the Pintler Mountains, Mountain Avens, Dryas octopetala, dominates the side walls of hexagonally patterned ground and narrow green stripes. At Glacier National Park, D. octopetala and the Arctic Willow, Salix arctica, co-dominate the green risers of widely-spaced striped periglacial patterned system at Siyeh Pass, while D. octopetala, S. arctica, and the Mountain Heather, Phyllodoce glanduliflora, co-dominate the green risers of the widely-spaced stripes of Piegan Pass. All four of these dictotyledonous angiosperm species are adventitiously-rooted dwarf shrubs with simple leaves. Of these, P. glanduliflora, A. uva-ursi and D. octopetala are evergreen. D. octopetala is symbiotic with N-fixing Frankia sp. All are mycorrhizal, although D. octopetala and S. arctica are ectomycorrhizal and P. glanduliflora and A. uva-ursi have ericaceous mycorrhizae. In contrast, dwarf shrubs are scarce on flat treads and within hexagons, which are chiefly inhabited by herbaceous, taprooted or rhizomatous, VAM angiosperms. As the green stripes and hexagon walls have greater plant cover, they likely have greater organic material due to leaf buildup and root turnover, anchor themselves and the soil with adventitious roots, their clonality suggests long lives, and N-fixing influences N dynamics of the periglacial patterned ground.

  7. Leaf Chlorophyll and Total Carotenoid Content, Barrow, Alaska, 2013-2015

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Alistair Rogers; Stefanie Lasota; Kim S. Ely

    Chlorophyll a, Chlorophyll b and total carotenoid content were determined on 146 samples collected from Arctic plant species within the Barrow Environmental Observatory in 2013 and 2015. Species sampled are Arctophila fulva, Arctagrostis latifolia, Carex aquatilis, Dupontia fisheri, Eriophorum angustifolium, Petasites frigidus, Salix pulchra, Vaccinium vitis-idaea, Salix rotundifolia, Luzula arctica and Saxifraga punctata.

  8. Macrobenthos of Yenisei Bay and the adjacent Kara Sea shelf

    NASA Astrophysics Data System (ADS)

    Galkin, S. V.; Vedenin, A. A.

    2015-07-01

    Trawl samples were collected in the northern region of Yenisei Bay and adjacent parts of the Kara Sea shelf. A total of eight stations were taken. We found more than 200 species of benthic organisms. A consecutive replacement of benthic communities is observed when going to the north from the Ob and Yenisei estuaries to the open parts of the sea. We could distinguish four different species complexes in the investigated area: a brackish-water complex where Saduria entomon is dominant; an intermediate complex where S. sibirica, S. sabini and Portlandia aestuariorum are dominant; a transitional complex with P. arctica as a dominant species and with a small amount of Ophiocten sericeum; a marine complex where O. sericeum is dominant. When salinity increased, some brackish-water species were replaced by related euryhaline species. One such example was the replacement of brackish-water Saduria entomon isopods by two euryhaline species: S. sibirica and S. sabini. The consecutive replacement of benthic communities showed a break near Sverdrup Island. In this area the marine complex was replaced by a transitional complex with P. arctica.

  9. The reindeer abomasal nematode (Ostertagia gruehneri) is naturally transmitted to sheep when sharing pastures.

    PubMed

    Manninen, Saana-Maaria; Thamsborg, Stig M; Laaksonen, Sauli; Oksanen, Antti

    2014-11-01

    The increasing number of sheep (Ovis aries) in northern Finland, often alternately corralled with winter-fed reindeer (Rangifer tarandus tarandus), creates potential for cross-infection of gastrointestinal nematodes. The aim of this study was to elucidate this possibility with 43 animals. Eleven reindeer and 8 sheep had shared a corral by turns, reindeer during winters, and sheep in summers. Another 12 reindeer had no known contact with sheep. Twelve sheep had no close contact to other ruminants. Both reindeer groups were free-ranging during summers. During slaughter in September to November, 2003, abomasa and parts of intestines were collected. Gastrointestinal nematodes were counted and identified. The species found were the following: in reindeer, Ostertagia gruehneri/Ostertagia arctica, Mazamastrongylus dagestanica, Nematodirus tarandi, Nematodirella longissimespiculata and Bunostomum trigonocephalum; in sheep, Teladorsagia circumcincta/Teladorsagia trifurcata, O. gruehneri/O. arctica, Nematodirus filicollis and N. spathiger. In the sheep sharing corral with reindeer, the only abomasal nematode species found was O. gruehneri, a reindeer parasite. The generation interval of O. gruehneri in Finnish reindeer appears to be shorter than in Canadian Arctic caribou, where complete larval inhibition leading to only one generation yearly has been reported.

  10. Revision of the Gonioctena nivosa species-group (Coleoptera, Chrysomelidae, Chrysomelinae) in the Holarctic region, with descriptions of two new species

    PubMed Central

    Cho, Hee-Wook; Kippenberg, Horst; Borowiec, Lech

    2016-01-01

    Abstract The Gonioctena nivosa species-group of the genus Gonioctena Chevrolat, 1836 is defined and reviewed. It contains six species including two new to science: Gonioctena gracilicornis (Kraatz, 1879), Gonioctena nivosa (Suffrian, 1851), Gonioctena norvegica (Strand, 1936), Gonioctena springlovae (Bechyně, 1948), Gonioctena amurensis Cho & Borowiec, sp. n. and Gonioctena jani Cho & Borowiec, sp. n. Six new synonyms are proposed: Gonioctena nivosa (= Gonioctena arctica alberta Brown, 1952, syn. n., Phytodecta linnaeana bergrothi Jacobson, 1901, syn. n., Phytodecta linnaeanus var. mutatus Achard, 1924, syn. n., Phytodecta linnaeanus var. simplex Achard, 1924, syn. n. and Phytodecta nivosa var. cedehensis Ronchetti, 1922, syn. n.) and Gonioctena norvegica (= Gonioctena janovskii Medvedev, 1976, syn. n.). Phytodecta flavicornis var. limbatipennis Achard, 1924 and Phytodecta nivosa var. bicolor Heyden, 1883 are removed from synonymy with Gonioctena nivosa (Suffrian, 1851) and are synonymized with Gonioctena flavicornis (Suffrian, 1851). Distribution maps, a key to species, color variation, geographic variation of male genitalia and host plants are provided. Ovoviviparity is newly recorded in Gonioctena gracilicornis and Gonioctena nivosa. Lectotypes are designated for Gonioctena affinis, Gonioctena arctica, Gonioctena linnaeana bergrothi and Gonioctena nivosa. PMID:27408579

  11. Intracellular pH Recovery Rates of Hemocytes from Estuarine and Open Ocean Bivalve Species Following In vitro Acid Challenge

    NASA Astrophysics Data System (ADS)

    Croxton, A.; Wikfors, G.

    2013-12-01

    Decreasing pH in estuarine systems is a growing concern for researchers studying mollusk species. Debates continue on whether estuarine bivalve species are more or less vulnerable to ocean acidification than marine species because estuaries can present multiple environmental stressors. The aim of this study is to understand the homeostatic mechanisms of bivalve hemocytes following exposure to extracellular acid treatment. Previous measurements using fluorescent SNARF probes and flow-cytometry have determined the intracellular pH of hemocytes from several bivalve species (eastern oyster, bay scallop, northern quahog, soft-shell clam, and blue mussel) to range between 7.0-7.4. In the present study of four bivalve species, recovery rate profiles were determined for intracellular hemocyte pH following addition of acid to hemolymph in vitro. These profiles indicate that soft-shell clams and bay scallops maintained homeostasis with very little change in intracellular pH. In contrast, an initial drop in intracellular pH in northern quahogs was followed by a steady recovery of intracellular pH. Contrasting results between species appear to be unrelated to mineral shell composition (aragonite vs. calcite) or habitat location (infaunal vs. epifaunal). The next phase of this study will be to determine if offshore species (surfclams and sea scallops) will have similar responses. Results from these studies will provide a better understanding of the physiological responses of estuarine and marine species exposed to acidified environments.

  12. Hydrothermal replacement of biogenic and abiogenic aragonite by Mg-carbonates - Relation between textural control on effective element fluxes and resulting carbonate phase

    NASA Astrophysics Data System (ADS)

    Jonas, Laura; Müller, Thomas; Dohmen, Ralf; Immenhauser, Adrian; Putlitz, Benita

    2017-01-01

    Dolomitization, i.e., the secondary replacement of calcite or aragonite (CaCO3) by dolomite (CaMg[CO3]2), is one of the most volumetrically important carbonate diagenetic processes. It occurs under near surface and shallow burial conditions and can significantly modify rock properties through changes in porosity and permeability. Dolomitization fronts are directly coupled to fluid pathways, which may be related to the initial porosity/permeability of the precursor limestone, an existing fault network or secondary porosity/permeability created through the replacement reaction. In this study, the textural control on the replacement of biogenic and abiogenic aragonite by Mg-carbonates, that are typical precursor phases in the dolomitization process, was experimentally studied under hydrothermal conditions. Aragonite samples with different textural and microstructural properties exhibiting a compact (inorganic aragonite single crystal), an intermediate (bivalve shell of Arctica islandica) and open porous structure (skeleton of coral Porites sp.) were reacted with a solution of 0.9 M MgCl2 and 0.015 M SrCl2 at 200 °C. The replacement of aragonite by a Ca-bearing magnesite and a Mg-Ca carbonate of non-stoichiometric dolomitic composition takes place via a dissolution-precipitation process and leads to the formation of a porous reaction front that progressively replaces the aragonite precursor. The reaction leads to the development of porosity within the reaction front and distinctive microstructures such as gaps and cavities at the reaction interface. The newly formed reaction rim consists of chemically distinct phases separated by sharp boundaries. It was found that the number of phases and their chemical variation decreases with increasing initial porosity and reactive surface area. This observation is explained by variations in effective element fluxes that result in differential chemical gradients in the fluid within the pore space of the reaction rim. Observed

  13. Profilicollis botulus (Van Cleave, 1916) from diving ducks and shore crabs of British Columbia.

    PubMed

    Ching, H L

    1989-02-01

    Adults of Profilicollis botulus were found in 6 species of diving ducks in British Columbia including 3 new hosts: common goldeneye, Bucephala clangula (L.); Barrow's goldeneye, B. islandica (Gmelin); and greater scaup, Aythya marila (L.). The identification of the species was verified by the examination of co-types and specimens from eider ducks, Somateria mollissima (L.), from Scotland and oldsquaw, Clangula hyemalis (L.), from New Brunswick. Cystacanths from the hairy shore crab, Hemigrapsus oregonensis (Dana), were similar in morphology to those from Carcinus maenas (L.) from Scotland.

  14. Inquiry Coaching: Scientists & Science Educators Energizing the Next Generation

    NASA Astrophysics Data System (ADS)

    Shope, R. E.; Alcantara Valverde, L.

    2007-05-01

    A recent National Academy of Sciences report recommends that science educators focus strategically on teaching the practice of science. To accomplish this, we have devised and implemented the Science Performance Laboratory, a collaborative research, education, and workforce model that brings scientists and science educators together to conduct scientific inquiry. In this session, we demonstrate how to form active inquiry teams around Arctica Science Research content areas related to the International Polar Year. We use the term "Arctica Science Research" to refer to the entire scope of exploration and discovery relating to: polar science and its global connections; Arctic and Antarctic research and climate sciences; ice and cryospheric studies on Earth; polar regions of the Moon, Mars, and Mercury; icy worlds throughout the Solar System, such as Europa, Enceladus, Titan, Pluto and the Comets; cryovolcanism; ice in interstellar space, and beyond. We apply the notion of teaching the practice science by enacting three effective strategies: 1) The Inquiry Wheel Game, in which we develop an expanded understanding of what has been traditionally taught as "the scientific method"; 2) Acting Out the Science Story, in which we develop a physicalized expression of our conceptual understanding; and 3) Selecting Success Criteria for Inquiry Coaching, in which we reframe how we evaluate science learning as we teach the practice of science.

  15. NQRY Coaching: Scientists and Science Educators Energizing the Next Generation

    NASA Astrophysics Data System (ADS)

    Shope, R. E.

    2007-12-01

    A recent National Academy of Science report recommends that science educators focus strategically on teaching the practice of science. To accomplish this, we have devised and implemented the Science Performance Collaboratory, a collaborative research, education, and workforce model that brings scientists and science educators together to conduct scientific inquiry. In this session, we demonstrate how to form active inquiry teams around Arctica Science Research content areas related to the International Polar Year. We use the term Arctica Science Research to refer to the entire scope of exploration and discovery relating to: polar science and its global connections; Arctic and Antarctic research and climate sciences; ice and cryospheric studies on Earth; polar regions of the Moon, Mars, and Mercury; icy worlds throughout the Solar System, such as Europa, Enceladus, Titan, Pluto and the Comets; cryovolvanism; ice in interstellar space, and beyond. We apply the notion of teaching the practice science by enacting three effective strategies: 1) The Inquiry Wheel Game, in which we develop an expanded understanding of what has been traditionally taught as "the scientific method"; 2) Acting Out the Science Story, in which we develop a physicalized expression of our conceptual understanding; and 3) Selecting Success Criteria for Inquiry Coaching, in which we reframe how we evaluate science learning as we teach the practice of science.

  16. Investigation of trophic ecology in Newfoundland cold-water deep-sea corals using lipid class and fatty acid analyses

    NASA Astrophysics Data System (ADS)

    Salvo, Flora; Hamoutene, Dounia; Hayes, Vonda E. Wareham; Edinger, Evan N.; Parrish, Christopher C.

    2018-03-01

    The trophic behavior of some deep-sea Newfoundland cold-water corals was explored using fatty acid (FA) and lipid profiles. No significant effect of geographic location and/or depth was identified in lipid or FA composition. However, differences were detected between and within taxon groups in hexa- or octocoral subclasses. Phospholipids constituted the main lipid class in all groups except black-thorny corals which had less structural lipids likely due to their morphology (stiff axes) and slower growth rates. Within each subclass, major differences in the identity of dominant FAs were detected at the order level, whereas differences between species and taxon groups of the same order were mainly driven by a variation in proportions of the dominant FA. Soft corals and gorgonians (Order Alcyonacea) were close in composition and are likely relying on phytodetritus resulting from algae, macrophytes and/or foraminifera, while sea pens (Order Pennatulacea) seem to consume more diatoms and/or herbivorous zooplankton with the exception of Pennatula sp. In the hexacoral subclass, black-thorny corals ( Stauropathes arctica) differed significantly from the stony-cup corals ( Flabellum alabastrum); S. arctica was seemingly more carnivorous (zooplankton markers) than F. alabastrum, which appears omnivorous (phyto- and zooplankton markers). Our results suggest that deep-sea corals are not as opportunistic as expected but have some selective feeding associated with taxonomy.

  17. Mud aprons in front of Svalbard surge moraines: Evidence of subglacial deforming layers or proglacial glaciotectonics?

    NASA Astrophysics Data System (ADS)

    Kristensen, Lene; Benn, Douglas I.; Hormes, Anne; Ottesen, Dag

    2009-10-01

    Large debris-flow units commonly occur on the distal sides of subaqueous end moraines deposited by surges of Svalbard tidewater glaciers, but have rarely been described in terrestrial settings. Some researchers have argued that these kinds of debris flows reflect processes unique to the subaqueous environment, such as the extrusion of subglacial deforming layers or extensive failure of oversteepened moraine fronts. In this paper, we describe terrestrial and subaqueous parts of a single late Holocene moraine system deposited by a major surge of the tidewater glacier Paulabreen in west Spitsbergen. The ice-marginal landforms on land closely resemble the corresponding landforms on the seabed as evidenced by geomorphic mapping and geophysical profiles from both environments. Both onland and offshore, extensive areas of hummocky moraine occur on the proximal side of the maximum glacier position, and large mud aprons (interpreted as debris flows) occur on the distal side. We show that the debris-flow sediments were pushed in front of the advancing glacier as a continuously failing, mobile push moraine. We propose that the mud aprons are end members of a proglacial landforms continuum that has thrust-block moraines as the opposite end member. Two clusters of dates (~ 8000 YBP and ~ 700 YBP) have previously been interpreted to indicate two separate surges responsible for the moraine formation. New dates suggest that the early cluster indicates a local extinction of the abounded species Chlamys islandica. Other changes corresponding to the widespread 8.2 ka event within the fjord, may suggest that the extinction of the C. islandica corresponds to that time.

  18. AROTAL Ozone and Temperature Vertical Profile Measurements from the NASA DC-8 during the SOLVE II Campaign

    NASA Technical Reports Server (NTRS)

    McGee, Thomas J.; Twigg, Laurence; Sumnicht, Grant; Hoegy, Walter; Burris, John; Silbert, Donald; Heaps, William; Neuber, R.; Trepte, C. R.

    2004-01-01

    The AROTAL instrument (Airborne Raman Ozone Temperature and Aerosol Lidar) - a collaboration between scientists at NASA Goddard Space Flight Center, and Langley Research Center - was flown on the NASA DC-8 during the SOLVE II Campaign during January and February, 2003. The flights were flown from the Arena Arctica in Kiruna, Sweden. We report measurements of temperature and ozone profiles showing approximately a 600 ppbv loss in ozone near 17.5 km, over the time frame of the aircraft campaign. Comparisons of ozone profiles from AROTAL are made with the SAGE III instrument.

  19. The fishery for Iceland scallop (Chlamys islandica) in the Northeast Atlantic.

    PubMed

    Garcia, Elena Guijarro

    2006-01-01

    This review focuses on the history and management of the Iceland scallop fishery in Iceland, Greenland and Norway (including the Svalbard archipelago and the islands of Bjørnøya and Jan Mayen), with information on research into each stock. The start of the fishery in all these regions followed the discovery of virgin scallop beds made up of old, large specimens in very high densities. Despite the apparent similarity of original conditions, the fishery has followed very different trends in each region, with drastic declines in Iceland, Svalbard and Jan Mayen. The general biology of the Iceland scallop is summarised and compared with the biology of other North Atlantic species of pectinids. The Icelandic fishery dates from 1969. There was a steady decrease in catch from 1985, when >16,000 tonnes were caught. By 2004 the stock had declined to 35% of its average size during the period 1993-2000 and a zero quota was advised. This decline is thought to have resulted from overexploitation, combined with a protozoan infestation and increasing sea bottom temperature. Scallop dredging commenced in west Greenland in 1983. The stock is not very large, but fishing was driven by social factors. Catches ranged from 400 to 1,900 tonnes during the period 1988-1992 and from 1,200 to 2,600 tonnes since 1995. There are indications that each scallop bed is extensively dredged before the fleet moves on to new areas, but nevertheless catches have been rather stable over the past decade. The scallop stocks in Svalbard, Bjørnøya and Jan Mayen were depleted in three fishing seasons between 1985-1987, when up to 45,000 tonnes of scallops were dredged in a single season. Following a survey carried out in 1991, Bjørnøya was open to the fishery with a maximum quota of 2,000 tonnes, but the stock off Svalbard was found to be not large enough to sustain a fishery.

  20. Gene expression changes governing extreme dehydration tolerance in an Antarctic insect

    PubMed Central

    Teets, Nicholas M.; Peyton, Justin T.; Colinet, Herve; Renault, David; Kelley, Joanna L.; Kawarasaki, Yuta; Lee, Richard E.; Denlinger, David L.

    2012-01-01

    Among terrestrial organisms, arthropods are especially susceptible to dehydration, given their small body size and high surface area to volume ratio. This challenge is particularly acute for polar arthropods that face near-constant desiccating conditions, as water is frozen and thus unavailable for much of the year. The molecular mechanisms that govern extreme dehydration tolerance in insects remain largely undefined. In this study, we used RNA sequencing to quantify transcriptional mechanisms of extreme dehydration tolerance in the Antarctic midge, Belgica antarctica, the world’s southernmost insect and only insect endemic to Antarctica. Larvae of B. antarctica are remarkably tolerant of dehydration, surviving losses up to 70% of their body water. Gene expression changes in response to dehydration indicated up-regulation of cellular recycling pathways including the ubiquitin-mediated proteasome and autophagy, with concurrent down-regulation of genes involved in general metabolism and ATP production. Metabolomics results revealed shifts in metabolite pools that correlated closely with changes in gene expression, indicating that coordinated changes in gene expression and metabolism are a critical component of the dehydration response. Finally, using comparative genomics, we compared our gene expression results with a transcriptomic dataset for the Arctic collembolan, Megaphorura arctica. Although B. antarctica and M. arctica are adapted to similar environments, our analysis indicated very little overlap in expression profiles between these two arthropods. Whereas several orthologous genes showed similar expression patterns, transcriptional changes were largely species specific, indicating these polar arthropods have developed distinct transcriptional mechanisms to cope with similar desiccating conditions. PMID:23197828

  1. Gene expression changes governing extreme dehydration tolerance in an Antarctic insect.

    PubMed

    Teets, Nicholas M; Peyton, Justin T; Colinet, Herve; Renault, David; Kelley, Joanna L; Kawarasaki, Yuta; Lee, Richard E; Denlinger, David L

    2012-12-11

    Among terrestrial organisms, arthropods are especially susceptible to dehydration, given their small body size and high surface area to volume ratio. This challenge is particularly acute for polar arthropods that face near-constant desiccating conditions, as water is frozen and thus unavailable for much of the year. The molecular mechanisms that govern extreme dehydration tolerance in insects remain largely undefined. In this study, we used RNA sequencing to quantify transcriptional mechanisms of extreme dehydration tolerance in the Antarctic midge, Belgica antarctica, the world's southernmost insect and only insect endemic to Antarctica. Larvae of B. antarctica are remarkably tolerant of dehydration, surviving losses up to 70% of their body water. Gene expression changes in response to dehydration indicated up-regulation of cellular recycling pathways including the ubiquitin-mediated proteasome and autophagy, with concurrent down-regulation of genes involved in general metabolism and ATP production. Metabolomics results revealed shifts in metabolite pools that correlated closely with changes in gene expression, indicating that coordinated changes in gene expression and metabolism are a critical component of the dehydration response. Finally, using comparative genomics, we compared our gene expression results with a transcriptomic dataset for the Arctic collembolan, Megaphorura arctica. Although B. antarctica and M. arctica are adapted to similar environments, our analysis indicated very little overlap in expression profiles between these two arthropods. Whereas several orthologous genes showed similar expression patterns, transcriptional changes were largely species specific, indicating these polar arthropods have developed distinct transcriptional mechanisms to cope with similar desiccating conditions.

  2. Identification and expression of the tig gene coding for trigger factor from psychrophilic bacteria with no information of genome sequence available.

    PubMed

    Lee, Kyunghee; Choi, Hyojung; Im, Hana

    2009-08-01

    Trigger factor (TF) plays a key role as a molecular chaperone with a peptidyl-prolyl cis-trans isomerase (PPIase) activity by which cells promote folding of newly synthesized proteins coming out of ribosomes. Since psychrophilic bacteria grow at a quite low temperature, between 4 and 15 degrees C, TF from such bacteria was investigated and compared with that of mesophilic bacteria E. coli in order to offer an explanation of cold-adaptation at a molecular level. Using a combination of gradient PCRs with homologous primers and LA PCR in vitro cloning technology, the tig gene was fully identified from Psychromonas arctica, whose genome sequence is not yet available. The resulting amino acid sequence of the TF was compared with other homologous TFs using sequence alignments to search for common domains. In addition, we have developed a protein expression system, by which TF proteins from P. arctica (PaTF) were produced by IPTG induction upon cloning the tig gene on expression vectors, such as pAED4. We have further examined the role of expressed psychrophilic PaTF on survival against cold treatment at 4 degrees C. Finally, we have attempted the in vitro biochemical characterization of TF proteins with His-tags expressed in a pET system, such as the PPIase activity of PaTF protein. Our results demonstrate that the expressed PaTF proteins helped cells survive against cold environments in vivo and the purified PaTF in vitro display the functional PPIase activity in a concentration dependent manner.

  3. Molecular characterisation of Sarcocystis lutrae n. sp. and Toxoplasma gondii from the musculature of two Eurasian otters (Lutra lutra) in Norway.

    PubMed

    Gjerde, Bjørn; Josefsen, Terje D

    2015-03-01

    the 18S and 28S rRNA genes and cox1, for which little or no sequence data were available for S. kalvikus, revealed that S. lutrae otherwise was most closely related to various Sarcocystis spp. using birds or carnivores as intermediate hosts. The cox1 sequences of S. lutrae from the otters were identical to two sequences from an arctic fox, which in a previous study had been assigned to Sarcocystis arctica due to a high identity (99.4 %) with the latter species at this gene and a complete identity with S. arctica at three other loci when using the same DNA samples as templates for PCR reactions. Additional PCR amplifications and sequencing of cox1 (ten sequences) and the ITS1 region (four sequences) using four DNA samples from this fox as templates again generated cox1 sequences exclusively of S. lutrae, but ITS1 sequences of S. arctica, and thus confirmed that this arctic fox had acted as intermediate host for both S. arctica and S. lutrae. Based on the phylogenetic placement of S. lutrae, the geographical location of infected animals (otters, arctic fox) and the distribution of carnivores/raptors which may have interacted with them, the white-tailed eagle (Haliaeetus albicilla) seems to be a possible definitive host of S. lutrae. Some of the muscle samples from both otters were shown to harbour stages of Toxoplasma gondii through PCR amplification and sequencing of the entire ITS1 region (five isolates) and/or the partial cytb (eight isolates) and cox1 (one isolate). These sequences were identical to several previous sequences of T. gondii in GenBank. Thus, both otters had a dual infection with S. lutrae and T. gondii.

  4. Behavior and Calibration of the Sr/Ca Temperature Proxy in Vesicomyid Clams

    NASA Astrophysics Data System (ADS)

    Hart, S. R.

    2009-12-01

    Clams of the Vesicomyidae family populate both hydrothermal vent areas and hydrocarbon cold seep areas. These habitats furnish reduced sulfides that support chemoautotrophic endosymbionts that nourish the clams. Clams of this family all grow aragonitic shells, and can have lifetimes that span many decades. The incorporation of Sr into aragonite in corals has a well-known temperature dependence and the same is true in clams, though the partitioning is reversed from that in corals. Thus the potential exists to use these clams to provide proxy temperatures for both hydrothermal and cold seep environments. Hart and Blusztajn (1998) used ion probe techniques for Sr/Ca analysis of several Calyptogena magnifica specimens from 10°N on the East Pacific Rise. Sub-monthly resolution was obtained, and large Sr/Ca variations were observed that could be correlated with known eruptive and venting episodes. The preliminary temperature calibration we reported in 1998 was obtained from an Arctica icelandica (ocean quahog), recovered from a coastal site with a 6 year instrumental temperature record (1.3° - 17.7°C). Because this species stops growing in the winter, the low temperature end of the calibration was uncertain. To refine this calibration, we report here Sr/Ca records from 3 cold seep localities (typically with 200+ analysis spots per clam): a Calyptogena ponderosa (Green Canyon, Gulf of Mexico, 720 m, ~ 6°C); a C. phaseoliformis? (Aleutian trench, 4922 m, 1.5°C); and paired C. pacifica and C. kilmeri (Monterey Canyon, 904 m, 4.2°C). All of these samples exhibited significant Sr/Ca variations, suggesting that either the sites were not isothermal (as hoped), or that the clams were processing water with anomalous, pore-water-derived, Sr/Ca. Significant stretches of each record did have low and fairly constant Sr/Ca and, when coupled with the known ambient water temperatures for each locality, substantiated a calibration only ~ 1° higher than the 1998 calibration (new

  5. A summary of alcid records from Hawaii

    USGS Publications Warehouse

    Clapp, R.B.

    1986-01-01

    Abstract.-Four species of alcids have now been recorded frorn Hawaii. Two of them, the Tufted Puffin (Fratercula cirrhata and the Cassin's Auklet (Ptychoramchus aleuticus) have been found only once; the occurrence of the latter is reported here for the first time. two other alcids, the Horned Puffin (Fratercula arctica) and the Parakeet .Auklet (Cyclorrhynchus psittacula) have been recorded frorn Hawaii in greater numbers; the latter may be of regular occurrence in subtropical waters near the northwestern portion of the Hawaiian archipelago. Occurrence in Hawaii does not appear to be strongly related to size of populations to the north but instead to the extent to which the species are known to disperse.

  6. Taxonomic revision of deep-sea Ostracoda from the Arctic Ocean

    USGS Publications Warehouse

    Yasuhara, Moriaki; Stepanova, Anna; Okahashi, Hisayo; Cronin, Thomas M.; Brouwers, Elisabeth M.

    2015-01-01

    Taxonomic revision of deep-sea Ostracoda from the Arctic Ocean was conducted to reduce taxonomic uncertainty that will improve our understanding of species ecology, biogeography and relationship to faunas from other deep-sea regions. Fifteen genera and 40 species were examined and (re-)illustrated with high-resolution scanning electron microscopy images, covering most of known deep-sea species in the central Arctic Ocean. Seven new species are described: Bythoceratina lomonosovensis n. sp., Cytheropteron parahamatum n. sp., Cytheropteron lanceae n. sp.,Cytheropteron irizukii n. sp., Pedicythere arctica n. sp., Cluthiawhatleyi n. sp., Krithe hunti n. sp. This study provides a robust taxonomic baseline for application to paleoceanographical reconstruction and biodiversity analyses in this climatically sensitive region.

  7. Special issue Oceans and Humans Health: the ecology of marine opportunists.

    PubMed

    Burge, Colleen A; Kim, Catherine J S; Lyles, Jillian M; Harvell, C Drew

    2013-05-01

    Opportunistic marine pathogens, like opportunistic terrestrial pathogens, are ubiquitous in the environment (waters, sediments, and organisms) and only cause disease in immune-compromised or stressed hosts. In this review, we discuss four host-pathogen interactions within the marine environment that are typically considered opportunistic: sea fan coral-fungus, eelgrass-Labyrinthula zosterae, sea fan-Labyrinthulomycetes, and hard clam-Quahog Parasite Unknown with particular focus on disease ecology, parasite pathology, host response, and known associated environmental conditions. Disease is a natural part of all ecosystems; however, in some cases, a shift in the balance between the host, pathogen, and the environment may lead to epizootics in natural or cultured populations. In marine systems, host-microbe interactions are less understood than their terrestrial counterparts. The biological and physical changes to the world's oceans, coupled with other anthropogenic influences, will likely lead to more opportunistic diseases in the marine environment.

  8. 76 FR 65180 - Proposed Information Collection; Comment Request; Application to Shuck Surf Clams/Ocean Quahogs...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-20

    .... Method of Collection Requests from allocation holders to transfer quota use paper applications or an... submitted on or before December 19, 2011. ADDRESSES: Direct all written comments to Diana Hynek... transferable quota (ITQ) allocation holders in order to process and track requests from the allocation holders...

  9. 75 FR 65580 - Fisheries of the Northeastern United States; Atlantic Surfclam and Ocean Quahog Fisheries...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-26

    ... data indicate that 30 percent of the Atlantic surfclam resource is smaller than 4.75 inches (120 mm... mm). Based on these data, the Regional Administrator adopts the Council's recommendation and suspends...

  10. A new species of Menestho Møller, 1842 from the Arctic with remarks on Menestho albula (Fabricius, 1780)(Gastropoda: Heterobranchia: Pyramidellidae).

    PubMed

    Nekhaev, Ivan O

    2017-11-10

    North Atlantic and Arctic representatives of the family Pyramidellidae had been intensively studied during the last decades. A valuable contribution was made by Warén (1989; 1991; 1993), who partially revised several genera from the Scandinavian waters. Norwegian representatives of the family were reviewed by Høisæter (2014). Distribution and diagnostic of many species had been specified by Schander (1995) and Nekhaev (2011; 2014; 2017). However, in the Eurasian Arctic Seas (except for the SW Barents Sea) only five species of Pyramidellidae had been recorded (Golikov et al. 2001; Kantor & Sysoev 2006; Nekhaev 2017): Liostomia eburnea (Stimpson, 1851), Chrysallida sublustris (Friele, 1886), Amaura candida (Møller, 1842), Amaura arctica (Dall et Bartsch, 1909) and Menestho truncatula Odhner, 1915.

  11. Plant Functional Traits on Green Risers and Brown Treads of Periglacial Patterned Ground at Glacier National Park, Montana

    NASA Astrophysics Data System (ADS)

    Apple, M. E.; Ricketts, M. K.

    2016-12-01

    On the stair-stepped solifluction terraces of the periglacial patterned ground at Glacier National Park, Montana, the clearly visible striped pattern of green alternating with brown is formed by contrasts in the percent cover of plants with different functional traits. The sloping green risers dominated by the mat-forming dwarf shrubs, Dryas octopetela (Mountain Dryad) and Salix arctica (Arctic Willow) alternate with the relatively flat, sparsely covered brown rocky treads which are inhabitated by herbaceous, and often taprooted plants. Eleven species were restricted to the brown treads, including the rare arctic-alpine species Papaver pygmaeum (Pygmy Poppy), Aqiulegia jonesii (Jones' Columbine), Draba macounii, and Erigeron lanatus. Of these, the first three arise from taproots or branched rootcrowns. They are restricted to the brown rocky treads while E. lanatus arises from a caudex and grows on the treads and risers. The relative abundance of rare plants was significantly higher on the brown treads and no rare species were restricted to the green risers. The community weighted trait means were significantly higher for Raunkiaer cryptophytes and hemicryptophytes, graminoid, herbaceous and rosetted forms, and stolons, Underground traits varied significantly as well, since taproots, caudices, and other substantial roots had higher incidences on the brown treads than on the green risers. The brown, rocky treads are relatively flat with low percent plant cover and likely a water-stressed environment, hence the substantial investment in underground structures. In contrast, the sloped green risers are essentially covered by the mat-forming dwarf shrubs, D. octopetela and S. arctica, which augment their woody roots with the anchorage of adventitious roots and which provide shade and water retention for other plants, including seedlings of Abies lasiocarpa (Subalpine fir) and Pinus albicaulus (Whitebark Pine). Water from summer thunderstorms and seasonal melting supplies

  12. Sea-ice induced growth decline in Arctic shrubs.

    PubMed

    Forchhammer, Mads

    2017-08-01

    Measures of increased tundra plant productivity have been associated with the accelerating retreat of the Arctic sea-ice. Emerging studies document opposite effects, advocating for a more complex relationship between the shrinking sea-ice and terrestrial plant productivity. I introduce an autoregressive plant growth model integrating effects of biological and climatic conditions for analysing individual ring-width growth time series. Using 128 specimens of Salix arctica , S. glauca and Betula nana sampled across Greenland to Svalbard, an overall negative effect of the retreating June sea-ice extent was found on the annual growth. The negative effect of the retreating June sea-ice was observed for younger individuals with large annual growth allocations and with little or no trade-off between previous and current year's growth. © 2017 The Author(s).

  13. Data Acquisition System for Russian Arctic Magnetometer Network

    NASA Astrophysics Data System (ADS)

    Janzhura, A.; Troshichev, O. A.; Takahashi, K.

    2010-12-01

    Monitoring of magnetic activity in the auroral zone is very essential for space weather problem. The big part of northern auroral zone lies in the Russian sector of Arctica. The Russian auroral zone stations are located far from the proper infrastructure and communications, and getting the data from the stations is complicated and nontrivial task. To resolve this problem a new acquisition system for magnetometers was implemented and developed in last few years, with the magnetic data transmission in real time that is important for many forecasting purpose. The system, based on microprocessor modules, is very reliable in hush climatic conditions. The information from the magnetic sensors transmits to AARI data center by satellite communication system and is presented at AARI web pages. This equipment upgrading of Russian polar magnetometer network is supported by the international RapidMag program.

  14. Shellfish depuration by gamma irradiation: Final report for the period October 1, 1985-September 30, 1986

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Beghian, L.; Melnick, J.

    1986-11-01

    Irradiation of live bivalve molluscs is a promising new technique to reduce the public health threats of viral and bacterial pathogens in the consumption of raw shellfish. In studies conducted within the past year, live hardshelled clams and oysters were innoculated with Simian Rotavirus SA-11, Poliovirus I, and Hepatitis-A virus and treated with gamma ray ionizing radiation from University of Lowell/DOE 800,000 Curie /sup 60/Co source over a dose range of 0.5--10 kiloGray (50--1000 kilorad) to determine the effectiveness of the process in eliminating viral activity and thus easing the potential viral health threats associated with uncooked bivalves. Two viralmore » strains, SA-11 and Poliovirus I, were employed as models to perfect laboratory technique and to estimate the most appropriate range of dose exposures necessary for optimal inactivation of the infectious pathogen, Hepatitis A. Post-irradiation survivorship of the oysters and quahogs was assessed over a range of exposures, and showed an exceptionally high degree of radioresistance for these molluscan species. 7 refs., 7 figs., 14 tabs.« less

  15. Examining diapirs as a nutrient source for plants in a High Arctic polar desert.

    NASA Astrophysics Data System (ADS)

    Hardy, Sarah; Siciliano, Steven

    2014-05-01

    Polar deserts cover a quarter of ice-free land in the Canadian Arctic, yet little is known about the key ecological processes that take place. This understudied ecosystem is becoming increasingly vulnerable to climate change and growth of the natural resource industry. In polar deserts, below ground soil masses called diapirs occur in some patterned ground features such as frost boils. Diapirs are formed above permafrost soil where increases in moisture and temperature stimulate biological activity when thawing occurs to create an organic rich, Bhy horizon. Vascular plants are scarce (< 5% cover) and nutrients for survival are likely supplied by diapirs but this interaction is poorly understood. To determine if diapirs are an important nutrient source, nitrogen and phosphorous were traced from the diapir Bhy to vascular plants using δ15N and δ18O stable isotope signatures. Recent developments have shown that the oxygen isotopes of orthophosphate (18OP) can be used to trace plant-available phosphorous. At a polar desert site at Alexandra Fjord, Canada, diapir (n=12) and non-diapir (n=12) frost boils were identified in 12 blocks with a field-portable vis-NIR (visible and near infrared spectrometer) device. Soil cores and Salix arctica plant tissue were collected from each frost boil for stable isotope analysis. The δ15N of Salix arctica plant tissue (n=144) shows a significant relationship between block location and diapir presence (p=0.003). There was a consistent pattern in average δ15N in plant tissue parts with increasing concentration from leaf, stem to root in all frost boils. There was no significant difference in total plant δ15N between diapir and non-diapir frost boils but δ15N in soil cores will be measured to determine if these signatures are attributed to the Bhy horizon or biological nitrogen fixation. These results highlight the potential for stable isotopes to be used as a nutrient tracer in polar desert ecosystems and further analysis of

  16. Expanded record of Quaternary oceanographic change: Amerasian Arctic Ocean

    USGS Publications Warehouse

    Ishman, S.E.; Polyak, L.V.; Poore, R.Z.

    1996-01-01

    Four sediment cores collected from the Northwind and Mendeleyev ridges, Arctic Ocean, from 1089 m to 1909 m water depth, provide an oceanographic record extending back into the Matuyama reversed polarity chron. Benthic foraminiferal analyses show four prominent assemblage zones: Bolivina arctica, Cassidulina teretis, Bulimina aculeata, and Oridorsalis tener from the upper Matuyama reversed polarity chronozone through the Brunhes normal polarity chronozone. These assemblage zones represent depth-dependent benthic foraminiferal biofacies changes associated with oceanographic events that occurred in the Amerasian basin at ??? 780 and 300 ka, and indicate oceanographic influence from the North Atlantic. Recognition of these benthic assemblage zones in Arctic cores from the Alpha Ridge indicates that the benthic foraminiferal zonations in intermediate to deep water (>1000 m) Arctic cores may be more useful than preexisting lithostratigraphic zonations and should provide important information pertaining to the Quaternary paleoceanographic evolution of the Arctic Ocean.

  17. Spatial variation in polycyclic aromatic hydrocarbon exposure in Barrow's goldeneye (Bucephala islandica) in coastal British Columbia.

    PubMed

    Willie, Megan; Esler, Daniel; Boyd, W Sean; Molloy, Philip; Ydenberg, Ronald C

    2017-05-15

    Barrow's goldeneyes are sea ducks that winter throughout coastal British Columbia (BC). Their diet consists primarily of intertidal blue mussels, which can accumulate PAHs; accordingly, goldeneyes may be susceptible to exposure through contaminated prey. In 2014/15, we examined total PAH concentrations in mussels from undeveloped and developed coastal areas of BC. At those same sites, we used EROD to measure hepatic CYP1A induction in goldeneyes. We found higher mussel PAH concentrations at developed coastal sites. Regionally, goldeneyes from southern BC, which has relatively higher coastal development, had higher EROD activity compared to birds from northern BC. Our results suggest goldeneyes wintering in coastal BC were exposed to PAHs through diet, with higher exposure among birds wintering in coastal areas with greater anthropogenic influence. These results suggest the mussel-goldeneye system is suitable as a natural, multi-trophic-level indicator of contemporary hydrocarbon contamination occurrence and exposure useful for establishing oil spill recovery endpoints. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Spatial variation in polycyclic aromatic hydrocarbon exposure in Barrow's goldeneye (Bucephala islandica) in coastal British Columbia

    USGS Publications Warehouse

    Willie, Megan; Esler, Daniel N.; Boyd, W. Sean; Molloy, Philip; Ydenberg, Ronald C.

    2017-01-01

    Barrow's goldeneyes are sea ducks that winter throughout coastal British Columbia (BC). Their diet consists primarily of intertidal blue mussels, which can accumulate PAHs; accordingly, goldeneyes may be susceptible to exposure through contaminated prey. In 2014/15, we examined total PAH concentrations in mussels from undeveloped and developed coastal areas of BC. At those same sites, we used EROD to measure hepatic CYP1A induction in goldeneyes. We found higher mussel PAH concentrations at developed coastal sites. Regionally, goldeneyes from southern BC, which has relatively higher coastal development, had higher EROD activity compared to birds from northern BC. Our results suggest goldeneyes wintering in coastal BC were exposed to PAHs through diet, with higher exposure among birds wintering in coastal areas with greater anthropogenic influence. These results suggest the mussel-goldeneye system is suitable as a natural, multi-trophic-level indicator of contemporary hydrocarbon contamination occurrence and exposure useful for establishing oil spill recovery endpoints.

  19. Onboard screening dockside testing as a new means of managing paralytic shellfish poisoning risks in federally closed waters

    NASA Astrophysics Data System (ADS)

    DeGrasse, Stacey; Conrad, Stephen; DiStefano, Paul; Vanegas, Camilo; Wallace, David; Jensen, Pete; Hickey, J. Michael; Cenci, Florence; Pitt, Jaclyn; Deardorff, Dave; Rubio, Fernando; Easy, Dorothy; Donovan, Mary Anne; Laycock, Maurice; Rouse, Debbie; Mullen, John

    2014-05-01

    Paralytic shellfish poisoning (PSP) is the foodborne intoxication associated with the consumption of seafood contaminated with naturally occurring neurotoxins known as paralytic shellfish toxins. To protect public health from this potentially fatal syndrome, harvesting closures are implemented when toxins exceed the regulatory action level. Traditional monitoring programs established by state shellfish authorities allow for timely closures in state waters with minimal negative impacts on industry. However, such monitoring programs are not feasible in federal offshore waters given their distance from shore and the range of their spatial coverage. Thus innovative management strategies were investigated for these offshore resources. Georges Bank, an offshore resource with an estimated market value of more than 3 billion in Atlantic surfclams and ocean quahogs, has been closed to harvesting following a temporary ban in 1989 and a subsequent indefinite closure in 1990 due to the risk of PSP. As a means of managing this risk and allowing harvest of safe shellfish from this important resource, the Onboard Screening Dockside Testing Protocol (referred to as the Protocol) was developed by the US Food and Drug Administration (FDA), National Marine Fisheries Service (NMFS), state shellfish control authorities, and industry. The Protocol, which sets forth control measures to ensure product safety and public health protection, was endorsed by the Interstate Shellfish Sanitation Conference (ISSC) for pilot testing. Briefly, the pilot study Protocol required that (1) the fishing vessel receive a permit from NMFS to harvest in closed waters, (2) a miniμm of five shellfish samples per intended harvest lot be tested for PSP toxins onboard, and (3) harvesting only occur when the samples tested from the intended fishing area are negative using the Jellett Rapid Tests or Abraxis Shipboard ELISA kits. Finally, product landed under the Protocol was confirmed to be safe for consumption

  20. The Arctic--A Global Hot Spot: Resources for Teaching the Geography of the Contemporary Canadian Arctic

    ERIC Educational Resources Information Center

    Arntzen, Betsy; Sotherden, Amy

    2011-01-01

    Canadian geography is a fascinating topic, particularly the Canadian North. The North is central to Canadian identity as can be seen by the choice of the far north "inukshuk" standing stones as the emblem for the 2010 Winter Olympics held in Vancouver, southern British Columbia. Canada's Arctic is receiving increasing attention by media,…

  1. Sarcocystis arctica (Apicomplexa: Sarcocystidae): ultrastructural description and its new host record, the Alaskan wolf (Canis lupus

    USDA-ARS?s Scientific Manuscript database

    Sarcocystis sarcocysts are common in muscles of herbivores but are rare in muscles of carnivores. Here, we report sarcocysts in muscle of an Alaskan wolf (Canis lupus) from Alaska, USA for the first time. Sarcocysts extracted from tongue of the wolf were up to 900 µm long, slender, and appeared to h...

  2. Influences of sea ice on eastern Bering Sea phytoplankton

    NASA Astrophysics Data System (ADS)

    Zhou, Qianqian; Wang, Peng; Chen, Changping; Liang, Junrong; Li, Bingqian; Gao, Yahui

    2015-03-01

    The influence of sea ice on the species composition and cell density of phytoplankton was investigated in the eastern Bering Sea in spring 2008. Diatoms, particularly pennate diatoms, dominated the phytoplankton community. The dominant species were Grammonema islandica (Grunow in Van Heurck) Hasle, Fragilariopsis cylindrus (Grunow) Krieger, F. oceanica (Cleve) Hasle, Navicula vanhoeffenii Gran, Thalassiosira antarctica Comber, T. gravida Cleve, T. nordenskiöeldii Cleve, and T. rotula Meunier. Phytoplankton cell densities varied from 0.08×104 to 428.8×104 cells/L, with an average of 30.3×104 cells/L. Using cluster analysis, phytoplankton were grouped into three assemblages defined by ice-forming conditions: open water, ice edge, and sea ice assemblages. In spring, when the sea ice melts, the phytoplankton dispersed from the sea ice to the ice edge and even into open waters. Thus, these phytoplankton in the sea ice may serve as a "seed bank" for phytoplankton population succession in the subarctic ecosystem. Moreover, historical studies combined with these results suggest that the sizes of diatom species have become smaller, shifting from microplankton to nannoplankton-dominated communities.

  3. Micro-Halocline Enabled Nutrient Recycling May Explain Extreme Azolla Event in the Eocene Arctic Ocean

    PubMed Central

    van Kempen, Monique M. L.; Smolders, Alfons J. P.; Lamers, Leon P. M.; Roelofs, Jan G. M.

    2012-01-01

    In order to understand the physicochemical mechanisms that could explain the massive growth of Azolla arctica in the Eocene Arctic Ocean, we carried out a laboratory experiment in which we studied the interacting effects of rain and wind on the development of salinity stratification, both in the presence and in the absence of a dense Azolla cover. Additionally, we carried out a mesocosm experiment to get a better understanding of the nutrient cycling within and beneath a dense Azolla cover in both freshwater and brackish water environments. Here we show that Azolla is able to create a windproof, small-scale salinity gradient in brackish waters, which allows for efficient recycling of nutrients. We suggest that this mechanism ensures the maintenance of a large standing biomass in which additional input of nutrients ultimately result in a further expansion of an Azolla cover. As such, it may not only explain the extent of the Azolla event during the Eocene, but also the absence of intact vegetative Azolla remains and the relatively low burial efficiency of organic carbon during this interval. PMID:23166833

  4. Micro-halocline enabled nutrient recycling may explain extreme Azolla event in the Eocene Arctic Ocean.

    PubMed

    van Kempen, Monique M L; Smolders, Alfons J P; Lamers, Leon P M; Roelofs, Jan G M

    2012-01-01

    In order to understand the physicochemical mechanisms that could explain the massive growth of Azolla arctica in the Eocene Arctic Ocean, we carried out a laboratory experiment in which we studied the interacting effects of rain and wind on the development of salinity stratification, both in the presence and in the absence of a dense Azolla cover. Additionally, we carried out a mesocosm experiment to get a better understanding of the nutrient cycling within and beneath a dense Azolla cover in both freshwater and brackish water environments. Here we show that Azolla is able to create a windproof, small-scale salinity gradient in brackish waters, which allows for efficient recycling of nutrients. We suggest that this mechanism ensures the maintenance of a large standing biomass in which additional input of nutrients ultimately result in a further expansion of an Azolla cover. As such, it may not only explain the extent of the Azolla event during the Eocene, but also the absence of intact vegetative Azolla remains and the relatively low burial efficiency of organic carbon during this interval.

  5. Acute fatal sarcocystosis hepatitis in an Indo-Pacific bottlenose dolphin (Tursiops aduncus) in Hong Kong.

    PubMed

    Calero-Bernal, R; Mauroo, N F; Hui, S W; Kuiken, T; van de Bildt, M W G; de Jong, A W; Osterhaus, A D M E; Sims, L; Gendron-Fitzpatrick, A; Carmena, D; Cerqueira-Cézar, C K; Rosenthal, B M; Dubey, J P

    2017-02-15

    Unlike most species in the genus Sarcocystis, Sarcocystis canis has a broad intermediate host range. Its life cycle is incompletely known and most reports are from the USA. Here we report fatal hepatitis in a 4year old male Indo-Pacific bottlenose dolphin (Tursiops aduncus) from Hong Kong associated with a S. canis-like infection. Diagnosis was made based on clinical presentation, histopathology, transmission electron microscopy (TEM), and molecular characterization. Microscopically, S. canis-like like infection was confined to the liver. Immature and mature schizonts were found in hepatocytes and the parasite was associated with generalized hepatic necrosis. By TEM, schizonts divided by endopolygeny, and merozoites lacked rhoptries. Molecular characterization of parasites present in liver and brain tissues at the cox1 gene showed a high degree of identity (97-98%) and clustered together with Sarcocystis canis, S. lutrae, S. arctica, S. speeri, S. turdusi, and S. rileyi in a phylogenetic study. This is the first report of S. canis-like infection from Asia. Published by Elsevier B.V.

  6. Approach to assess consequences of hypoxia disturbance events for benthic ecosystem functioning

    NASA Astrophysics Data System (ADS)

    Gogina, Mayya; Darr, Alexander; Zettler, Michael L.

    2014-01-01

    Our study challenges the functional approach for its usefulness in assessing the consequences of hypoxia disturbance events on macrofaunal communities in the south-western Baltic Sea. Time series for two decades of observations from two monitoring stations, one in the Fehmarnbelt (exposed to aperiodic hypoxia), and another in the Darss Rise (normoxic conditions) is used. Our results designate differences of functional structure of benthic fauna communities between sites based on biological traits that characterise species role in modifying the environment, behavioural strategies, morphology and life history, thus suggesting differences in functioning. Hypoxic years reveal sharp increase of the role of sedentary species, suspension filter feeders, epibenthic structures, globulose form, medium/large size of individuals, preponderance of species with long lifespan (caused for instance by remaining ocean quahog). The link of functional and species diversity to the stagnation periods is proposed for the Darss station that exhibit continuous changes and low temporal variability of traits distribution. Before the major inflow in 1993 the increased role of small size organisms, containing calcium carbonate, filter feeders and grazers, higher presence of semi-pelagic species is observed. The hypoxic events and water renewal processes impact the communities not only in respect to species composition but also functionally.

  7. Individual specialization in a shorebird population with narrow foraging niche

    NASA Astrophysics Data System (ADS)

    Catry, Teresa; Alves, José A.; Gill, Jennifer A.; Gunnarsson, Tómas G.; Granadeiro, José P.

    2014-04-01

    Individual specialization in resource use is a widespread driver for intra-population trait variation, playing a crucial evolutionary role in free-living animals. We investigated the individual foraging specialization of Black-tailed Godwits (Limosa limosa islandica) during the wintering period. Godwits displayed distinct degrees of individual specialization in diet and microhabitat use, indicating the presence of both generalist and specialist birds. Females were overall more specialist than males, primarily consuming polychaetes. Specialist males consumed mainly bivalves, but some individuals also specialized on gastropods or polychaetes. Sexual dimorphism in bill length is probably important in determining the differences in specialization, as longer-billed individuals have access to deep-buried polychaetes inaccessible to most males. Different levels of specialization within the same sex, unrelated to bill length, were also found, suggesting that mechanisms other traits are involved in explaining individual specialization. Godwits specialized on bivalves achieved higher intake rates than non-specialist birds, supporting the idea that individual foraging choices or skills result in different short-term payoffs within the same population. Understanding whether short-term payoffs are good indicators of long-term fitness and how selection operates to favour the prevalence of specialist or generalist godwits is a major future challenge.

  8. Densities of Barrow's goldeneyes during winter in Prince William Sound, Alaska in relation to habitat, food, and history of oil contamination

    USGS Publications Warehouse

    Esler, Daniel N.; Bowman, Timothy D.; O'Clair, Charles E.; Dean, Thomas A.; McDonald, Lyman L.

    2000-01-01

    We evaluated variation in densities of Barrow's Goldeneyes (Bucephala islandica) during winter at 214 sites within oiled and unoiled study areas in Prince William Sound, Alaska in relation to physical habitat attributes, prey biomass, and history of habitat contamination by the 1989 Exxon Valdez oil spill. Using general linear model analyses, we found that goldeneye densities were positively associated with occurrence of a stream within 200 m, lack of exposure to wind and waves, and mixed (versus rocky) substrate. We speculate that these associations relate to habitat profitability via selection of beneficial attributes and avoidance of detrimental features. We also determined that biomass of blue mussels (Mytilus trossulus), the primary prey, was not related to Barrow's Goldeneye densities; we suggest that mussel standing stock exceeds predation demands in our study areas and, thus, does not dictate goldeneye distribution. After accounting for habitat effects, we detected no effect of history of oil contamination on Barrow's Goldeneye densities, suggesting that populations have recovered from the oil spill. Although other studies documented hydrocarbon exposure in Barrow's Goldeneyes through at least 1997, either the level of exposure did not affect populations via reductions in survival, or effects of oil exposure were offset by immigration.

  9. Late Pleistocene mammoth remains from Coastal Maine, USA

    USGS Publications Warehouse

    Hoyle, B.G.; Fisher, D.C.; Borns, H.W.; Churchill-Dickson, L. L.; Dorion, C.C.; Weddle, T.K.

    2004-01-01

    Remains identified as those of a woolly mammoth ( Mammuthus primigenius ) dated at 12,200 ?? 55 14C yr B.P. were recovered while excavating in a complex sequence of glaciomarine sediments in Scarborough, Maine, USA. The mammoth was found in the top meter of a fossiliferous unit of mud and sand laminites. These sediments were deposited during a marine regressive phase following the transgression that accompanied northward retreat of the margin of the Laurentide ice sheet. A Portlandia arctica valve from the underlying transgressive unit provides a minimum age of 14,820 ?? 105 14C yr B.P. for local deglaciation. The mammoth, an adult female, died in midwinter with no evidence of human involvement. Tusk growth rates and oxygen-isotope variation over the last few years of life record low seasonality. The mammoth was transported to the site as a partial carcass by the late-glacial proto-Saco River. It sank in a near-shore setting, was subjected to additional disarticulation and scattering of elements, and was finally buried in sediments reworked by the shallowing sea. ?? 2004 University of Washington. All rights reserved.

  10. ER-2 #809 awaits pilot entry for the third flight of the SAGE III Ozone Loss and Validation Experiment (SOLVE)

    NASA Image and Video Library

    2000-01-28

    ER-2 #809 awaiting pilot entry for the third flight of the SAGE III Ozone Loss and Validation Experiment (SOLVE). The ER-2, a civilian variant of Lockheed's U-2, and another NASA flying laboratory, Dryden's DC-8, were based north of the Arctic Circle in Kiruna, Sweden during the winter of 2000 to study ozone depletion as part of SOLVE. A large hangar built especially for research, "Arena Arctica" housed the instrumented aircraft and the scientists. Scientists have observed unusually low levels of ozone over the Arctic during recent winters, raising concerns that ozone depletion there could become more widespread as in the Antarctic ozone hole. The NASA-sponsored international mission took place between November 1999 and March 2000 and was divided into three phases. The DC-8 was involved in all three phases returning to Dryden between each phase. The ER-2 flew sample collection flights between January and March, remaining in Sweden from Jan. 9 through March 16. "The collaborative campaign will provide an immense new body of information about the Arctic stratosphere," said program scientist Dr. Michael Kurylo, NASA Headquarters. "Our understanding of the Earth's ozone will be greatly enhanced by this research."

  11. Structure of the pelagic cnidarian community in Lützow-Holm Bay in the Indian sector of the Southern Ocean

    NASA Astrophysics Data System (ADS)

    Toda, R.; Moteki, M.; Ono, A.; Horimoto, N.; Tanaka, Y.; Ishimaru, T.

    2010-08-01

    The structure of the pelagic cnidarian community in Lützow-Holm Bay in the Indian sector of East Antarctica was investigated in January 2005 and 2006. Zooplankton samples from six discrete depths (surface to 2000 m) obtained using an RMT-8 yielded 4666 individuals of 31 species of cnidarian. Cnidarian abundance and carbon biomass were far greater in 2005 than in 2006. The biomass of macrozooplankton was large in the upper 200 m in 2005, but concentrated at 200-500 m in 2006, except for Euphausiacea. The most dominant species was Diphyes antarctica, followed by Dimophyes arctica and Muggiaea bargmannae. Four species had never been collected from East Antarctica; of these, Solmissus incisa was a first record in the Southern Ocean. Cluster analysis revealed the following three major communities: the epipelagic (0-200 m), in summer surface, winter, and upper modified circumpolar deep waters (MCDW); the upper mesopelagic (200-500 m), in upper MCDW; and the lower meso- and bathypelagic (500-2000 m), in lower MCDW. The epipelagic and lower meso- and bathypelagic communities are likely reduced in abundance/biomass when primary production is low, due to bottom-up control, while the upper mesopelagic community remains stable.

  12. Intracellular pH Recovery Rates in Bivalve Hemocytes Following Exposure to Acidic Environmental Conditions

    NASA Astrophysics Data System (ADS)

    Croxton, A.; Wikfors, G. H.

    2012-12-01

    Predictions of ocean acidification effects upon carbonate shell-forming species have caused great concern for the future of shellfisheries. Nevertheless, bivalve species inhabiting an estuarine environment have evolved in these environments with fluctuating pH levels. Previous experimental studies conducted in our laboratory have demonstrated the ability of oyster hemocytes to maintain intracellular homeostasis under acidic external conditions. However, little information is known of this homeostatic mechanism in other molluscan shellfish species present in these same habitats. In the current study we propose to determine if other bivalve species of aquaculture interest also possess this intracellular regulation by applying an in vitro hemocyte pH-recovery assay, previously developed for oysters, on the northern quahog, Mercenaria mercenaria, the blue mussel, Mytilus edulis, and the softshell clam, Mya arenaria. Preliminary results from the determination of initial intracellular pH levels, the initial step in the rate recovery assay, indicated a pH range between 7.0-7.4. This range was comparable to initial values measured in oysters, and consistent with data reported in the current literature. The second step of the hemocyte pH-recovery assay involves exposing oyster hemocytes to acidic external conditions and measuring the ability of the hemocyte intracellular pH to maintain homeostasis (i.e. recovery rate). Results from the recovery rate process will be presented.

  13. Toxicity of ammonia to three marine fish and three marine invertebrates.

    PubMed

    Boardman, Gregory D; Starbuck, Steven M; Hudgins, Douglas B; Li, Xiayoun; Kuhn, David D

    2004-04-01

    Laboratory toxicity tests were performed to obtain more data on the toxicity of ammonia to saltwater organisms. The standards for in-stream ammonia limits in marine environments presently are based on toxicity tests involving both freshwater and saltwater organisms. Acute tests (48 and 96 h) were performed at 20 degrees C, and chronic tests (7 days) were performed at 25 degrees C. Synthetic seawater and natural seawater from the Chesapeake Bay were used and compared. Included among the organisms tested were sheepshead minnow (14 days old), summer flounder (2 months old), Atlantic silverside (14 days old), mysid shrimp (less than 2 days old), ghost shrimp (10 days old), and quahog clam (9 months old). Based on these results, it seems the chronic criterion for ammonia in marine environments could be increased from 0.035 to 0.081 mg/L un-ionized ammonia, which would, of course, increase the chronic limit for total ammonia under typical saltwater conditions by a factor of 2.31. No difference was observed in the toxicity of ammonia in natural water compared to synthetic water for both the summer flounder and Atlantic silverside. Furthermore, the Atlantic silverside became more sensitive to ammonia as the salinity was increased from 14 to 22 ppt, but exhibited no change in toxicity response from 22 to 30 ppt. Copyright 2004 Wiley Periodicals, Inc. Environ Toxicol 19: 134-142, 2004

  14. A simple method to reduce the risk of cadmium exposure from consumption of Iceland scallops (Chlamys islandica) fished in Greenland.

    PubMed

    Bach, Lis; Sonne, Christian; Rigét, Frank F; Dietz, Rune; Asmund, Gert

    2014-08-01

    This paper studied the levels and organ distribution of the toxic heavy metal cadmium in scallops from unpolluted Greenlandic waters. The scallops had an average cadmium concentration of 2.93 ± 0.94 μg/g wet weight in the total soft tissues and no concentration dependent effect was found for gender or size (both p>0.05). The kidney was the primary organ for cadmium accumulation with a mean of 226.2 ± 111.7 μg/g wet weight, and despite the small weight of the kidney, it appeared as the principal contributor of cadmium with 92% of the total cadmium body burden. The cadmium concentrations in the total soft tissues far exceeded the EU-limit of 1 μg/g wet weight for cadmium in bivalves. Based on this, selective evisceration of the cadmium-rich kidney and digestive gland during processing can be regarded as a reliable measure to be taken in order to reduce the cadmium content of scallops used for human consumption. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Shellfish dredging pushes a flexible avian top predator out of a marine protected area.

    PubMed

    van Gils, Jan A; Piersma, Theunis; Dekinga, Anne; Spaans, Bernard; Kraan, Casper

    2006-11-01

    There is a widespread concern about the direct and indirect effects of industrial fisheries; this concern is particularly pertinent for so-called "marine protected areas" (MPAs), which should be safeguarded by national and international law. The intertidal flats of the Dutch Wadden Sea are a State Nature Monument and are protected under the Ramsar convention and the European Union's Habitat and Birds Directives. Until 2004, the Dutch government granted permission for ~75% of the intertidal flats to be exploited by mechanical dredgers for edible cockles (Cerastoderma edule). Here we show that dredged areas belonged to the limited area of intertidal flats that were of sufficient quality for red knots (Calidris canutus islandica), a long-distance migrant molluscivore specialist, to feed. Dredging led to relatively lower settlement rates of cockles and also reduced their quality (ratio of flesh to shell). From 1998 to 2002, red knots increased gizzard mass to compensate for a gradual loss in shellfish quality, but this compensation was not sufficient and led to decreases in local survival. Therefore, the gradual destruction of the necessary intertidal resources explains both the loss of red knots from the Dutch Wadden Sea and the decline of the European wintering population. This study shows that MPAs that do not provide adequate protection from fishing may fail in their conservation objectives.

  16. Shellfish Dredging Pushes a Flexible Avian Top Predator out of a Marine Protected Area

    PubMed Central

    van Gils, Jan A; Piersma, Theunis; Dekinga, Anne; Spaans, Bernard; Kraan, Casper

    2006-01-01

    There is a widespread concern about the direct and indirect effects of industrial fisheries; this concern is particularly pertinent for so-called “marine protected areas” (MPAs), which should be safeguarded by national and international law. The intertidal flats of the Dutch Wadden Sea are a State Nature Monument and are protected under the Ramsar convention and the European Union's Habitat and Birds Directives. Until 2004, the Dutch government granted permission for ~75% of the intertidal flats to be exploited by mechanical dredgers for edible cockles (Cerastoderma edule). Here we show that dredged areas belonged to the limited area of intertidal flats that were of sufficient quality for red knots (Calidris canutus islandica), a long-distance migrant molluscivore specialist, to feed. Dredging led to relatively lower settlement rates of cockles and also reduced their quality (ratio of flesh to shell). From 1998 to 2002, red knots increased gizzard mass to compensate for a gradual loss in shellfish quality, but this compensation was not sufficient and led to decreases in local survival. Therefore, the gradual destruction of the necessary intertidal resources explains both the loss of red knots from the Dutch Wadden Sea and the decline of the European wintering population. This study shows that MPAs that do not provide adequate protection from fishing may fail in their conservation objectives. PMID:17105350

  17. Multi-decadal changes in the megabenthos of the Bay of Fundy: The effects of fishing

    NASA Astrophysics Data System (ADS)

    Kenchington, Ellen L.; Kenchington, Trevor J.; Henry, Lea-Anne; Fuller, Susanna; Gonzalez, Patricia

    2007-10-01

    Analysis of presence / absence records from two comparable megabenthic surveys of scallop grounds in the Bay of Fundy, Canada, in 1966-67 and 1997 showed profound change over three decades. There were no indications that any species were lost and the average number of taxa per station remained steady. However, spatial heterogeneities in the community were reduced and species composition changed significantly. Some taxa widespread in 1966-67 declined while others expanded, with frequencies of occurrence of individual taxa changing by up to 71%. The whelks Buccinum undatum and Colus spp., the bivalves Astarte spp. and Cyclocardia borealis, the toad crabs Hyas spp., the sea urchin Strongylocentrotus droebachiensis and the brittle stars (Ophiurida) showed particular increases. Corresponding declines were seen in the boring sponges Cliona spp., the horse mussel Modiolus modiolus, the scallop Chlamys islandica, the fan worm Pseudopotamilla reniformis and the stalked tunicate Boltenia ovifera. Replacement of attached, fragile, epifaunal, filter-feeding taxa by a combination of motile scavengers, motile filter-feeders and robust, burrowing filter-feeders suggests that the primary cause of the temporal change was physical impacts by fishing gear, even though trawling and scallop dragging in the area were neither intense nor new developments. Secondary causes of change may have included other ecosystem effects of fishing (supply of discards and bait), a mass mortality of scallops and a range expansion of a bryozoan ( Flustra foliacea).

  18. Stable C and N isotopic composition of cold-water corals from the Newfoundland and Labrador continental slope: Examination of trophic, depth and spatial effects

    NASA Astrophysics Data System (ADS)

    Sherwood, Owen A.; Jamieson, Robyn E.; Edinger, Evan N.; Wareham, Vonda E.

    2008-10-01

    With the aim of understanding of the trophic ecology of cold-water corals, this paper explores the tissue δ13C and δ15N values of 11 'coral' species (8 alcyonacean, 1 antipatharian, 1 pennatulacean, 1 scleractinian) collected along the Newfoundland and Labrador continental slope. Isotopic results delimit species along continua of trophic level and food lability. With an isotopic signature similar to macrozooplankton, Paragorgia arborea occupies the lowest trophic level and most likely feeds on fresh phytodetritus. Primnoa resedaeformis occupies a slightly higher trophic level, likely supplementing its diet with microzooplankton. Bathypathes arctica, Pennatulacea and other alcyonaceans ( Acanella arbuscula, Acanthogorgia armata, Anthomastus grandiflorus, Duva florida, Keratoisis ornata, Paramuricea sp.) had higher δ13C and δ15N values, suggesting these species feed at higher trophic levels and on a greater proportion of more degraded POM. Flabellum alabastrum had an isotopic signature similar to that of snow crab, indicating a primarily carnivorous diet. Isotopic composition did not vary significantly over a depth gradient of 50-1400 m. Coral δ13C increased slightly (<1‰) from the Hudson Strait to the southern Grand Banks, but δ15N did not. By modulating the availability and quality of suspended foods, substrate likely exerts a primary influence on the feeding habits of cold-water corals.

  19. Exopolymer alteration of physical properties of sea ice and implications for ice habitability and biogeochemistry in a warmer Arctic

    PubMed Central

    Krembs, Christopher; Eicken, Hajo; Deming, Jody W.

    2011-01-01

    The physical properties of Arctic sea ice determine its habitability. Whether ice-dwelling organisms can change those properties has rarely been addressed. Following discovery that sea ice contains an abundance of gelatinous extracellular polymeric substances (EPS), we examined the effects of algal EPS on the microstructure and salt retention of ice grown from saline solutions containing EPS from a culture of the sea-ice diatom, Melosira arctica. We also experimented with xanthan gum and with EPS from a culture of the cold-adapted bacterium Colwellia psychrerythraea strain 34H. Quantitative microscopic analyses of the artificial ice containing Melosira EPS revealed convoluted ice-pore morphologies of high fractal dimension, mimicking features found in EPS-rich coastal sea ice, whereas EPS-free (control) ice featured much simpler pore geometries. A heat-sensitive glycoprotein fraction of Melosira EPS accounted for complex pore morphologies. Although all tested forms of EPS increased bulk ice salinity (by 11–59%) above the controls, ice containing native Melosira EPS retained the most salt. EPS effects on ice and pore microstructure improve sea ice habitability, survivability, and potential for increased primary productivity, even as they may alter the persistence and biogeochemical imprint of sea ice on the surface ocean in a warming climate. PMID:21368216

  20. Exopolymer alteration of physical properties of sea ice and implications for ice habitability and biogeochemistry in a warmer Arctic.

    PubMed

    Krembs, Christopher; Eicken, Hajo; Deming, Jody W

    2011-03-01

    The physical properties of Arctic sea ice determine its habitability. Whether ice-dwelling organisms can change those properties has rarely been addressed. Following discovery that sea ice contains an abundance of gelatinous extracellular polymeric substances (EPS), we examined the effects of algal EPS on the microstructure and salt retention of ice grown from saline solutions containing EPS from a culture of the sea-ice diatom, Melosira arctica. We also experimented with xanthan gum and with EPS from a culture of the cold-adapted bacterium Colwellia psychrerythraea strain 34H. Quantitative microscopic analyses of the artificial ice containing Melosira EPS revealed convoluted ice-pore morphologies of high fractal dimension, mimicking features found in EPS-rich coastal sea ice, whereas EPS-free (control) ice featured much simpler pore geometries. A heat-sensitive glycoprotein fraction of Melosira EPS accounted for complex pore morphologies. Although all tested forms of EPS increased bulk ice salinity (by 11-59%) above the controls, ice containing native Melosira EPS retained the most salt. EPS effects on ice and pore microstructure improve sea ice habitability, survivability, and potential for increased primary productivity, even as they may alter the persistence and biogeochemical imprint of sea ice on the surface ocean in a warming climate.

  1. Comparative population structure of cavity-nesting sea ducks

    USGS Publications Warehouse

    Pearce, John M.; Eadie, John M.; Savard, Jean-Pierre L.; Christensen, Thomas K.; Berdeen, James; Taylor, Eric J.; Boyd, Sean; Einarsson, Árni

    2014-01-01

    A growing collection of mtDNA genetic information from waterfowl species across North America suggests that larger-bodied cavity-nesting species exhibit greater levels of population differentiation than smaller-bodied congeners. Although little is known about nest-cavity availability for these species, one hypothesis to explain differences in population structure is reduced dispersal tendency of larger-bodied cavity-nesting species due to limited abundance of large cavities. To investigate this hypothesis, we examined population structure of three cavity-nesting waterfowl species distributed across much of North America: Barrow's Goldeneye (Bucephala islandica), Common Goldeneye (B. clangula), and Bufflehead (B. albeola). We compared patterns of population structure using both variation in mtDNA control-region sequences and band-recovery data for the same species and geographic regions. Results were highly congruent between data types, showing structured population patterns for Barrow's and Common Goldeneye but not for Bufflehead. Consistent with our prediction, the smallest cavity-nesting species, the Bufflehead, exhibited the lowest level of population differentiation due to increased dispersal and gene flow. Results provide evidence for discrete Old and New World populations of Common Goldeneye and for differentiation of regional groups of both goldeneye species in Alaska, the Pacific Northwest, and the eastern coast of North America. Results presented here will aid management objectives that require an understanding of population delineation and migratory connectivity between breeding and wintering areas. Comparative studies such as this one highlight factors that may drive patterns of genetic diversity and population trends.

  2. Sea-ice eukaryotes of the Gulf of Finland, Baltic Sea, and evidence for herbivory on weakly shade-adapted ice algae.

    PubMed

    Majaneva, Markus; Blomster, Jaanika; Müller, Susann; Autio, Riitta; Majaneva, Sanna; Hyytiäinen, Kirsi; Nagai, Satoshi; Rintala, Janne-Markus

    2017-02-01

    To determine community composition and physiological status of early spring sea-ice organisms, we collected sea-ice, slush and under-ice water samples from the Baltic Sea. We combined light microscopy, HPLC pigment analysis and pyrosequencing, and related the biomass and physiological status of sea-ice algae with the protistan community composition in a new way in the area. In terms of biomass, centric diatoms including a distinct Melosira arctica bloom in the upper intermediate section of the fast ice, dinoflagellates, euglenoids and the cyanobacterium Aphanizomenon sp. predominated in the sea-ice sections and unidentified flagellates in the slush. Based on pigment analyses, the ice-algal communities showed no adjusted photosynthetic pigment pools throughout the sea ice, and the bottom-ice communities were not shade-adapted. The sea ice included more characteristic phototrophic taxa (49%) than did slush (18%) and under-ice water (37%). Cercozoans and ciliates were the richest taxon groups, and the differences among the communities arose mainly from the various phagotrophic protistan taxa inhabiting the communities. The presence of pheophytin a coincided with an elevated ciliate biomass and read abundance in the drift ice and with a high Eurytemora affinis read abundance in the pack ice, indicating that ciliates and Eurytemora affinis were grazing on algae. Copyright © 2016 Elsevier GmbH. All rights reserved.

  3. DC-8 during takeoff in Kiruna, Sweden for the second flight of the SAGE III Ozone Loss and Validatio

    NASA Technical Reports Server (NTRS)

    2000-01-01

    NASA's DC-8 taking off from the Kiruna, Sweden, runway in January 2000. The weather at this town of 25,000, located north of the Arctic Circle, can be severe. Temperatures drop as low as 50 degrees below zero Fahrenheit. In December 1999, when the SAGE III Ozone Loss and Validation Experiment (SOLVE) deployment began, there were 20 days of darkness. By mid-January 2000, there was 5 hours of daylight, while in mid-February this increased to nine hours per day. The population of Kiruna extended its hospitality to the SOLVE personnel. On January 22, 2000, the town hosted a dinner for the participants and media attending an open house at the Arena Arctica hangar. At the end of the SOLVE deployment, the airborne science team held an open house for the townspeople at the facility. NASA is using a DC-8 aircraft as a flying science laboratory. The platform aircraft, based at NASA's Dryden Flight Research Center, Edwards, Calif., collects data for many experiments in support of scientific projects serving the world scientific community. Included in this community are NASA, federal, state, academic and foreign investigators. Data gathered by the DC-8 at flight altitude and by remote sensing have been used for scientific studies in archeology, ecology, geography, hydrology, meteorology, oceanography, volcanology, atmospheric chemistry, soil science and biology.

  4. Climate change alters leaf anatomy, but has no effects on volatile emissions from Arctic plants.

    PubMed

    Schollert, Michelle; Kivimäenpää, Minna; Valolahti, Hanna M; Rinnan, Riikka

    2015-10-01

    Biogenic volatile organic compound (BVOC) emissions are expected to change substantially because of the rapid advancement of climate change in the Arctic. BVOC emission changes can feed back both positively and negatively on climate warming. We investigated the effects of elevated temperature and shading on BVOC emissions from arctic plant species Empetrum hermaphroditum, Cassiope tetragona, Betula nana and Salix arctica. Measurements were performed in situ in long-term field experiments in subarctic and high Arctic using a dynamic enclosure system and collection of BVOCs into adsorbent cartridges analysed by gas chromatography-mass spectrometry. In order to assess whether the treatments had resulted in anatomical adaptations, we additionally examined leaf anatomy using light microscopy and scanning electron microscopy. Against expectations based on the known temperature and light-dependency of BVOC emissions, the emissions were barely affected by the treatments. In contrast, leaf anatomy of the studied plants was significantly altered in response to the treatments, and these responses appear to differ from species found at lower latitudes. We suggest that leaf anatomical acclimation may partially explain the lacking treatment effects on BVOC emissions at plant shoot-level. However, more studies are needed to unravel why BVOC emission responses in arctic plants differ from temperate species. © 2015 The Authors. Plant, Cell & Environment published by John Wiley & Sons Ltd.

  5. Scale-dependent correlation of seabirds with schooling fish in a coastal ecosystem

    USGS Publications Warehouse

    Schneider, Davod C.; Piatt, John F.

    1986-01-01

    The distribution of piscivorous seabirds relative to schooling fish was investigated by repeated censusing of 2 intersecting transects in the Avalon Channel, which carries the Labrador Current southward along the east coast of Newfoundland. Murres (primarily common murres Uria aalge), Atlantic puffins Fratercula arctica, and schooling fish (primarily capelin Mallotus villosus) were highly aggregated at spatial scales ranging from 0.25 to 15 km. Patchiness of murres, puffins and schooling fish was scale-dependent, as indicated by significantly higher variance-to-mean ratios at large measurement distances than at the minimum distance, 0.25 km. Patch scale of puffins ranged from 2.5 to 15 km, of murres from 3 to 8.75 km, and of schooling fish from 1.25 to 15 km. Patch scale of birds and schooling fish was similar m 6 out of 9 comparisons. Correlation between seabirds and schooling birds was significant at the minimum measurement distance in 6 out of 12 comparisons. Correlation was scale-dependent, as indicated by significantly higher coefficients at large measurement distances than at the minimum distance. Tracking scale, as indicated by the maximum significant correlation between birds and schooling fish, ranged from 2 to 6 km. Our analysis showed that extended aggregations of seabirds are associated with extended aggregations of schooling fish and that correlation of these marine carnivores with their prey is scale-dependent.

  6. ER-2 #809 outside Arena Arctica hangar in Kiruna, Sweden prior to the SAGE III Ozone Loss and Validation Experiment (SOLVE)

    NASA Image and Video Library

    2000-01-24

    ER-2s bearing tail numbers 806 and 809 are used as airborne science platforms by NASA's Dryden Flight Research Center. The aircraft are platforms for a variety of high-altitude science missions flown over various parts of the world. They are also used for earth science and atmospheric sensor research and development, satellite calibration and data validation. The ER-2s are capable of carrying a maximum payload of 2,600 pounds of experiments in a nose bay, the main equipment bay behind the cockpit, two wing-mounted superpods and small underbody and trailing edges. Most ER-2 missions last about six hours with ranges of about 2,200 nautical miles. The aircraft typically fly at altitudes above 65,000 feet. On November 19, 1998, an ER-2 set a world record for medium weight aircraft reaching an altitude of 68,700 feet. The aircraft is 63 feet long, with a wingspan of 104 feet. The top of the vertical tail is 16 feet above ground when the aircraft is on the bicycle-type landing gear. Cruising speeds are 410 knots, or 467 miles per hour, at altitude. A single General Electric F-118 turbofan engine rated at 17,000 pounds thrust powers the ER-2.

  7. Previously unknown apicomplexan species infecting Iceland scallop, Chlamys islandica (Müller, 1776), queen scallop, Aequipecten opercularis L., and king scallop, Pecten maximus L.

    PubMed

    Kristmundsson, Árni; Helgason, Sigurður; Bambir, Slavko Helgi; Eydal, Matthías; Freeman, Mark A

    2011-11-01

    Examination of three scallop species from three separate locations: Iceland scallop from Icelandic waters, king scallop from Scottish waters and queen scallop from Faroese and Scottish waters, revealed infections of a previously unknown apicomplexan parasite in all three scallop species. Developmental forms observed in the shells appeared to include both sexual and asexual stages of the parasite, i.e. merogony, gametogony and sporogony, which suggests a monoxenous life cycle. Meronts, gamonts, zygotes and mature oocysts were solely found in the muscular tissue. Zoites, which could be sporozoites and/or merozoites, were observed in great numbers, most frequently in muscles, both intracellular and free in the extracellular space. Zoites were also common inside haemocytes. Examination of the ultrastructure showed that the zoites contained all the major structures characterizing apicomplexans. This apicomplexan parasite is morphologically different from other apicomplexan species previously described from bivalves. Presently, its systematic position within the phylum Apicomplexa cannot be ascertained. Copyright © 2011 Elsevier Inc. All rights reserved.

  8. Characterization of MHC class I in a long distance migratory wader, the Icelandic black-tailed godwit.

    PubMed

    Pardal, Sara; Drews, Anna; Alves, José A; Ramos, Jaime A; Westerdahl, Helena

    2017-07-01

    The major histocompatibility complex (MHC) encodes proteins that are central for antigen presentation and pathogen elimination. MHC class I (MHC-I) genes have attracted a great deal of interest among researchers in ecology and evolution and have been partly characterized in a wide range of bird species. So far, the main focus has been on species within the bird orders Galliformes and Passeriformes, while Charadriiformes remain vastly underrepresented with only two species studied to date. These two Charadriiformes species exhibit striking differences in MHC-I characteristics and MHC-I diversity. We therefore set out to study a third species within Charadriiformes, the Icelandic subspecies of black-tailed godwits (Limosa limosa islandica). This subspecies is normally confined to parasite-poor environments, and we hence expected low MHC diversity. MHC-I was partially characterized first using Sanger sequencing and then using high-throughput sequencing (MiSeq) in 84 individuals. We verified 47 nucleotide alleles in open reading frame with classical MHC-I characteristics, and each individual godwit had two to seven putatively classical MHC alleles. However, in contrast to previous MHC-I data within Charadriiformes, we did not find any evidence of alleles with low sequence diversity, believed to represent non-classical MHC genes. The diversity and divergence of the godwits MHC-I genes to a large extent fell between the previous estimates within Charadriiformes. However, the MHC genes of the migratory godwits had few sites subject to positive selection, and one possible explanation could be a low exposure to pathogens.

  9. Element accumulation in boreal bryophytes, lichens and vascular plants exposed to heavy metal and sulfur deposition in Finland.

    PubMed

    Salemaa, Maija; Derome, John; Helmisaari, Heljä-Sisko; Nieminen, Tiina; Vanha-Majamaa, Ilkka

    2004-05-25

    Macronutrient (N, P, K, Mg, S, Ca), heavy metal (Fe, Zn, Mn, Cu, Ni, Cd, Pb) and Al concentrations in understorey bryophytes, lichens and vascular plant species growing in Scots pine forests at four distances from the Harjavalta Cu-Ni smelter (0.5, 2, 4 and 8 km) were compared to those at two background sites in Finland. The aim was to study the relationship between element accumulation and the distribution of the species along a pollution gradient. Elevated sulfur, nitrogen and heavy metal concentrations were found in all species groups near the pollution source. Macronutrient concentrations tended to decrease in the order: vascular plants>bryophytes>lichens, when all the species groups grew on the same plot. Heavy metal concentrations (except Mn) were the highest in bryophytes, followed by lichens, and were the lowest in vascular plants. In general, vascular plants, being capable of restricting the uptake of toxic elements, grew closer to the smelter than lichens, while bryophytes began to increase in the understorey vegetation at further distances from the smelter. A pioneer moss (Pohlia nutans) was an exception, because it accumulated considerably higher amounts of Cu and Ni than the other species and still survived close to the smelter. The abundance of most of the species decreased with increasing Cu and Ni concentrations in their tissues. Cetraria islandica, instead, showed a positive relationship between the abundance and Cu, Ni and S concentrations of the thallus. It is probable that, in addition to heavy metals, sporadically high SO(2) emissions have also affected the distribution of the plant species.

  10. A direct estimate of poleward volume, heat, and freshwater fluxes at 59.5°N between Greenland and Scotland

    NASA Astrophysics Data System (ADS)

    Rossby, T.; Reverdin, Gilles; Chafik, Leon; Søiland, Henrik

    2017-07-01

    The meridional overturning circulation (MOC) in the North Atlantic plays a major role in the transport of heat from low to high latitudes. In this study, we combine recent measurements of currents from the surface to >700 m from a shipboard acoustic Doppler current profiler with Argo profiles (to 2000 m) to estimate poleward volume, heat, and freshwater flux at 59.5°N between Greenland and Scotland. This is made possible thanks to the vessel Nuka Arctica that operates on a 3 week schedule between Greenland and Denmark. For the period late 2012 to early 2016, the deseasoned mean meridional overturning circulation reaches a 18.4 ± 3.4 Sv maximum at the σθ = 27.55 kg m-3 isopycnal, which varies in depth from near the surface in the western Irminger Sea to 1000 m in Rockall Trough. The total heat and freshwater fluxes across 59.5°N = 399 ± 74 TW and -0.20 ± 0.04 Sv, where the uncertainties are principally due to that of the MOC. Analysis of altimetric sea surface height variations along exactly the same route reveals a somewhat stronger geostrophic flow north during this period compared to the 23 year mean suggesting that for a long-term mean the above flux estimates should be reduced slightly to 17.4 Sv, 377 TW, and -0.19 Sv, respectively, with the same estimate uncertainties. The ADCP program is ongoing.

  11. Relative Abundance of Nitrotoga spp. in a Biofilter of a Cold-Freshwater Aquaculture Plant Appears To Be Stimulated by Slightly Acidic pH

    PubMed Central

    Hüpeden, Jennifer; Wegen, Simone; Off, Sandra; Lücker, Sebastian; Bedarf, Yvonne; Daims, Holger; Kühn, Carsten

    2016-01-01

    The functioning of recirculation aquaculture systems (RAS) is essential to maintain water quality for fish health, and one crucial process here is nitrification. The investigated RAS was connected to a rainbow trout production system and operated at an average temperature of 13°C and pH 6.8. Community analyses of the nitrifying biofilm revealed a coexistence of Nitrospira and Nitrotoga, and it is hypothesized that a slightly acidic pH in combination with lower temperatures favors the growth of the latter. Modification of the standard cultivation approach toward lower pH values of 5.7 to 6.0 resulted in the successful enrichment (99% purity) of Nitrotoga sp. strain HW29, which had a 16S rRNA sequence similarity of 99.0% to Nitrotoga arctica. Reference cultures of Nitrospira defluvii and the novel Nitrotoga sp. HW29 were used to confirm differentiation of these nitrite oxidizers in distinct ecological niches. Nitrotoga sp. HW29 revealed pH and temperature optima of 6.8 and 22°C, respectively, whereas Nitrospira defluvii displayed the highest nitrite oxidation rate at pH 7.3 and 32°C. We report here the occurrence of Nitrotoga as one of the main nitrite-oxidizing bacteria in freshwater aquaculture systems and indicate that a slightly acidic pH, in addition to temperatures below 20°C, can be applied as a selective isolation criterion for this microorganism. PMID:26746710

  12. Influence of Environmental Changes on Physiology and Development of Polar Vascular Plants

    NASA Astrophysics Data System (ADS)

    Giełwanowska, Irena; Pastorczyk, Marta; Kellmann-Sopyła, Wioleta

    2011-01-01

    Polar vascular plants native to the Arctic and the Antarctic geobotanical zone have been growing and reproducing effectively under difficult environmental conditions, colonizing frozen ground areas formerly covered by ice. Our macroscopic observations and microscopic studies conducted by means of a light microscope (LM) and transmission electron microscope (TEM) concerning the anatomical and ultrastructural observations of vegetative and generative tissue in Cerastium arcticum, Colobanthus quitensis, Silene involucrata, plants from Caryophyllaceae and Deschampsia antarctica, Poa annua and Poa arctica, from Poaceae family. In the studies, special attention was paid to plants coming from diversity habitats where stress factors operated with clearly different intensity. In all examinations plants, differences in anatomy were considerable. In Deschampsia antarctica the adaxial epidermis of hairgrass leaves from a humid microhabitat, bulliform cells differentiated. Mesophyll was composed of cells of irregular shapes and resembled aerenchyma. The ultrastructural observations of mesophyll in all plants showed tight adherence of chloroplasts, mitochondria and peroxisomes, surface deformations of these organelles and formation of characteristic outgrowths and pocket concavities filled with cytoplasm with vesicles and organelles by chloroplasts. In reproduction biology of examined Caryophyllaceae and Poaceae plants growing in natural conditions, in the Arctic and in the Antarctic, and in a greenhouse in Olsztyn showed that this plant develops two types of bisexual flowers. Almost all ovules developed and formed seeds with a completely differentiated embryo both under natural conditions in the Arctic and the Antarctic and in a greenhouse in Olsztyn.

  13. Seismic stratigraphy of sedimentary cover in Amerasian Basin based on the results of Russian High Arctic expeditions

    NASA Astrophysics Data System (ADS)

    Poselov, Viktor; Kireev, Artem; Smirnov, Oleg; Butsenko, Viktor; Zholondz, Sergey; Savin, Vasily

    2016-04-01

    Massive amount of multichannel seismic (MCS) data were obtained by Russian High Arct ic expeditions "Arctica-2011", "Acrtica-2012" and "Arctica-2014". More than 40 MCS lines are located in the Amerasian basin and help to substantiate the seismic stratigraphy model of its sedimentary cover. The proposed seismic stratigraphy model was successively determined for the Cenozoic and pre-Cenozoic parts of the sedimentary section and was based on correlation of the Russian MCS data and seismic data documented by boreholes. Cenozoic part of the sedimentary cover is based on correlation of the Russian MCS data and AWI91090 section calibrated by ACEX-2004 boreholes on the Lomonosov Ridge. Two major unconformities are traced. The upper regional unconformity (RU) is associated with a major pre-Miocene hiatus. Another major hiatus is recorded in the borehole section between the Campanian and the Upper Paleocene units. It is recognized as the post-Campanian unconformity (pCU) in the seismic sections. Formation of the regional unconformities is associated with a fundamental change in depositional environment. Formation of RU was initiated by opening of the Fram Strait gateway at the Paleogene/Neogene boundary. Post-Campanian unconformity is linked with the initial stage of the Eurasian Basin opening between the Cretaceous and the Paleogene. Cenozoic sedimentary units are continuously traced from the East-Siberian and Chukchi sea shelves across the transit zone to the Amerasian basin. Paleogene unit (between pCU and RU) is formed under the neritic depositional environment and it is characterized by an extremely small thickness on the Lomonosov Ridge (less than 200 m), on the Mendeleev Rise and in the Podvodnikov Basin (not more than 300-400 m). Neogene unit (above RU) consists of hemipelagic deposits and occupies the essential part of thickness of the Cenozoic section in Podvodnikov and Makarov Basins. Interval velocities in the Paleogene unit vary within 2.8-3.2 km/s, in the

  14. Diagenetic susceptibility of carbonate archives - an experimental approach

    NASA Astrophysics Data System (ADS)

    Pederson, C.; Purgstaller, B.; Mavromatis, V.; Dietzel, M.; Jöns, N.; Buhl, D.; Neuser, R. D.; Breitenbach, S. F. M.; Hoffmann, R.; Kwiecien, O.; Riechelmann, S.; Immenhauser, A.

    2017-12-01

    Carbonate sediments and biominerals can record environmental conditions during both deposition and subsequent diagenesis, making them important archives of within the geologic record. Therefore, the alteration processes of these paleoenvironmental proxies are important to understand if one is to deduce environmental conditions based on their petrographic and geochemical signature. This study uses an experimental approach in order to best indicate the controls and effects of the diagenesis of various carbonate archives. Samples are hydrothermally altered at known conditions including pore water chemistry (meteoric and brine fluids), and temperature (100-200°C), and are directly compared to an unaltered subsample (same specimen) for petrographic and geochemical alteration, allowing for reduced heterogeneity, and a quantitative and systematic approach to determine the type, extent, and controls of diagenesis. Initial results indicate little-no alteration at the lower temperature experiments (100°C), and almost complete alteration observed at higher temperatures (175-200°C), while intermediate temperature ranges (130-160°C) prove promising for the evaluation of both diagenetic mechanisms, as well as rate limiting factors controlling alteration. Initial results indicate partial recrystallization of the bivalve A. Islandica, as well as other carbonates (corals, bivalves, gastropods, ammonites, and speleothems), with a visually distinct recrystallization front for select specimens. Results indicate that the diagenetic pathway preferentially follows organic distribution, and internal structures within the organo-sediments and minerals, possibly formed during initial formation. Alteration also suggests preferential movement of intercrystalline organics in some sample types, where they appear to be pushed away from the diagenetic front, causing concentration of the water insoluble organics, and the production of visually darker areas surrounding diagenetic fluid pathways.

  15. Climate, copepods and seabirds in the boreal Northeast Atlantic - current state and future outlook.

    PubMed

    Frederiksen, Morten; Anker-Nilssen, Tycho; Beaugrand, Grégory; Wanless, Sarah

    2013-02-01

    The boreal Northeast Atlantic is strongly affected by current climate change, and large shifts in abundance and distribution of many organisms have been observed, including the dominant copepod Calanus finmarchicus, which supports the grazing food web and thus many fish populations. At the same time, large-scale declines have been observed in many piscivorous seabirds, which depend on abundant small pelagic fish. Here, we combine predictions from a niche model of C. finmarchicus with long-term data on seabird breeding success to link trophic levels. The niche model shows that environmental suitability for C. finmarchicus has declined in southern areas with large breeding seabird populations (e.g. the North Sea), and predicts that this decline is likely to spread northwards during the 21st century to affect populations in Iceland and the Faroes. In a North Sea colony, breeding success of three common piscivorous seabird species [black-legged kittiwake (Rissa tridactyla), common guillemot (Uria aalge) and Atlantic puffin (Fratercula arctica)] was strongly positively correlated with local environmental suitability for C. finmarchicus, whereas this was not the case at a more northerly colony in west Norway. Large seabird populations seem only to occur where C. finmarchicus is abundant, and northward distributional shifts of common boreal seabirds are therefore expected over the coming decades. Whether or not population size can be maintained depends on the dispersal ability and inclination of these colonial breeders, and on the carrying capacity of more northerly areas in a warmer climate. © 2012 Blackwell Publishing Ltd.

  16. Pliocene Seasonality along the US Atlantic Coastal Plain Inferred from Growth Increment Analysis of Mercenaria carolinensis

    NASA Astrophysics Data System (ADS)

    Winkelstern, I. Z.; Surge, D. M.

    2010-12-01

    Pliocene sea surface temperature (SST) data from the US Atlantic coastal plain is currently insufficient for a detailed understanding of the climatic shifts that occurred during the period. Previous studies, based on oxygen isotope proxy data from marine shells and bryozoan zooid size analysis, have provided constraints on possible annual-scale SST ranges for the region. However, more data are required to fully understand the forcing mechanisms affecting regional Pliocene climate and evaluate modeled temperature projections. Bivalve sclerochronology (growth increment analysis) is an alternative proxy for SST that can provide annually resolved multi-year time series. The method has been validated in previous studies using modern Arctica, Chione, and Mercenaria. We analyzed Pliocene Mercenaria carolinensis shells using sclerochronologic methods and tested the hypothesis that higher SST ranges are reflected in shells selected from the warmest climate interval (3.5-3.3 Ma, upper Yorktown Formation, Virginia) and lower SST ranges are observable in shells selected from the subsequent cooling interval (2.4-1.8 Ma, Chowan River Formation, North Carolina). These results further establish the validity of growth increment analysis using fossil shells and provide the first large dataset (from the region) of reconstructed annual SST from floating time series during these intervals. These data will enhance our knowledge about a warm climate state that has been identified in the 2007 IPCC report as an analogue for expected global warming. Future work will expand this study to include sampling in Florida to gain detailed information about Pliocene SST along a latitudinal gradient.

  17. Spatial and temporal variation of an ice-adapted predator's feeding ecology in a changing Arctic marine ecosystem.

    PubMed

    Yurkowski, David J; Ferguson, Steven H; Semeniuk, Christina A D; Brown, Tanya M; Muir, Derek C G; Fisk, Aaron T

    2016-03-01

    Spatial and temporal variation can confound interpretations of relationships within and between species in terms of diet composition, niche size, and trophic position (TP). The cause of dietary variation within species is commonly an ontogenetic niche shift, which is a key dynamic influencing community structure. We quantified spatial and temporal variations in ringed seal (Pusa hispida) diet, niche size, and TP during ontogeny across the Arctic-a rapidly changing ecosystem. Stable carbon and nitrogen isotope analysis was performed on 558 liver and 630 muscle samples from ringed seals and on likely prey species from five locations ranging from the High to the Low Arctic. A modest ontogenetic diet shift occurred, with adult ringed seals consuming more forage fish (approximately 80 versus 60 %) and having a higher TP than subadults, which generally decreased with latitude. However, the degree of shift varied spatially, with adults in the High Arctic presenting a more restricted niche size and consuming more Arctic cod (Boreogadus saida) than subadults (87 versus 44 %) and adults at the lowest latitude (29 %). The TPs of adult and subadult ringed seals generally decreased with latitude (4.7-3.3), which was mainly driven by greater complexity in trophic structure within the zooplankton communities. Adult isotopic niche size increased over time, likely due to the recent circumpolar increases in subarctic forage fish distribution and abundance. Given the spatial and temporal variability in ringed seal foraging ecology, ringed seals exhibit dietary plasticity as a species, suggesting adaptability in terms of their diet to climate change.

  18. Sterol and genomic analyses validate the sponge biomarker hypothesis.

    PubMed

    Gold, David A; Grabenstatter, Jonathan; de Mendoza, Alex; Riesgo, Ana; Ruiz-Trillo, Iñaki; Summons, Roger E

    2016-03-08

    Molecular fossils (or biomarkers) are key to unraveling the deep history of eukaryotes, especially in the absence of traditional fossils. In this regard, the sterane 24-isopropylcholestane has been proposed as a molecular fossil for sponges, and could represent the oldest evidence for animal life. The sterane is found in rocks ∼650-540 million y old, and its sterol precursor (24-isopropylcholesterol, or 24-ipc) is synthesized today by certain sea sponges. However, 24-ipc is also produced in trace amounts by distantly related pelagophyte algae, whereas only a few close relatives of sponges have been assayed for sterols. In this study, we analyzed the sterol and gene repertoires of four taxa (Salpingoeca rosetta, Capsaspora owczarzaki, Sphaeroforma arctica, and Creolimax fragrantissima), which collectively represent the major living animal outgroups. We discovered that all four taxa lack C30 sterols, including 24-ipc. By building phylogenetic trees for key enzymes in 24-ipc biosynthesis, we identified a candidate gene (carbon-24/28 sterol methyltransferase, or SMT) responsible for 24-ipc production. Our results suggest that pelagophytes and sponges independently evolved C30 sterol biosynthesis through clade-specific SMT duplications. Using a molecular clock approach, we demonstrate that the relevant sponge SMT duplication event overlapped with the appearance of 24-isopropylcholestanes in the Neoproterozoic, but that the algal SMT duplication event occurred later in the Phanerozoic. Subsequently, pelagophyte algae and their relatives are an unlikely alternative to sponges as a source of Neoproterozoic 24-isopropylcholestanes, consistent with growing evidence that sponges evolved long before the Cambrian explosion ∼542 million y ago.

  19. Ocean-wide Drivers of Migration Strategies and Their Influence on Population Breeding Performance in a Declining Seabird.

    PubMed

    Fayet, Annette L; Freeman, Robin; Anker-Nilssen, Tycho; Diamond, Antony; Erikstad, Kjell E; Fifield, Dave; Fitzsimmons, Michelle G; Hansen, Erpur S; Harris, Mike P; Jessopp, Mark; Kouwenberg, Amy-Lee; Kress, Steve; Mowat, Stephen; Perrins, Chris M; Petersen, Aevar; Petersen, Ib K; Reiertsen, Tone K; Robertson, Gregory J; Shannon, Paula; Sigurðsson, Ingvar A; Shoji, Akiko; Wanless, Sarah; Guilford, Tim

    2017-12-18

    Which factors shape animals' migration movements across large geographical scales, how different migratory strategies emerge between populations, and how these may affect population dynamics are central questions in the field of animal migration [1] that only large-scale studies of migration patterns across a species' range can answer [2]. To address these questions, we track the migration of 270 Atlantic puffins Fratercula arctica, a red-listed, declining seabird, across their entire breeding range. We investigate the role of demographic, geographical, and environmental variables in driving spatial and behavioral differences on an ocean-basin scale by measuring puffins' among-colony differences in migratory routes and day-to-day behavior (estimated with individual daily activity budgets and energy expenditure). We show that competition and local winter resource availability are important drivers of migratory movements, with birds from larger colonies or with poorer local winter conditions migrating further and visiting less-productive waters; this in turn led to differences in flight activity and energy expenditure. Other behavioral differences emerge with latitude, with foraging effort and energy expenditure increasing when birds winter further north in colder waters. Importantly, these ocean-wide migration patterns can ultimately be linked with breeding performance: colony productivity is negatively associated with wintering latitude, population size, and migration distance, which demonstrates the cost of competition and migration on future breeding and the link between non-breeding and breeding periods. Our results help us to understand the drivers of animal migration and have important implications for population dynamics and the conservation of migratory species. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Distribution of siphonophores, chaetognaths, euphausiids and oceanographic conditions in the fjords and channels of southern Chile

    NASA Astrophysics Data System (ADS)

    Palma, Sergio; Silva, Nelson

    2004-03-01

    Interior waters of the fjords and channels of southern Chile (41.5°S-56°S) receive inputs of Subantarctic Water, Equatorial Subsuperficial Water and Western Pacific Subsurface Water from the adjacent Pacific Ocean by means of numerous connecting channels that lead inward from the ocean margin. These waters become mixed in the interior zone with freshwater from precipitation, river flow, and meltwater from cordilleran glaciers. A two-layered positive estuarine circulation becomes established, with a superficial layer having a net movement towards the adjacent ocean, and a deep layer with net movement towards the fjords. The biomass of the interior waters is composed principally of planktonic crustaceans (copepods and euphausiids), chaetognaths, and gelatinous carnivores. In a southerly direction, decreases are observed in biomass, in relative abundance, and in species diversity of siphonophores, chaetognaths, and euphausiids. Only a few species have been able to adapt successfully to the extreme oceanographic conditions typical of the region, reflected in dominant monospecific populations such as Muggiaea atlantica, Sagitta tasmanica, and Euphausia vallentini. The zooplankton fauna of interior waters, characterized by its low degree of specific richness, is made up of a mixture of species typical of Subantarctic Water (Sagitta tasmanica, S. decipiens, Euphausia lucens, Nematoscelis megalops, Thysanoessa gregaria), antarctic water (Pyrosthephos vanhoeffeni, Dimophyes arctica, Sagitta marri, S. gazellae, Eukrohnia hamata, E. bathyantarctica, Euphausia vallentini), temperate and warm epipelagic waters (Eudoxoides spiralis, Lensia conoidea, Chelophyes appendiculata, Muggiaea atlantica, Sphaeronectes gracilis, S. fragilis, Abylopsis tetragona, Sagitta enflata), and mesopelagic water (Physophora hydrostatica, Stylocheiron maximum, Vogtia pentacantha, V. serrata).

  1. Influence of Environmental Changes on Physiology and Development of Polar Vascular Plants

    NASA Astrophysics Data System (ADS)

    Giełwanowska, Irena; Pastorczyk, Marta; Kellmann-Sopyła, Wioleta

    2011-01-01

    Polar vascular plants native to the Arctic and the Antarctic geobotanical zone have been growing and reproducing effectively under difficult environmental conditions, colonizing frozen ground areas formerly covered by ice. Our macroscopic observations and microscopic studies conducted by means of a light microscope (LM) and transmission electron microscope (TEM) concerning the anatomical and ultrastructural observations of vegetative and generative tissue in Cerastium arcticum, Colobanthus quitensis, Silene involucrata, plants from Caryophyllaceae and Deschampsia antarctica, Poa annua and Poa arctica, from Poaceae family. In the studies, special attention was paid to plants coming from diversity habitats where stress factors operated with clearly different intensity. In all examinations plants, differences in anatomy were considerable. In Deschampsia antarctica the adaxial epidermis of hairgrass leaves from a humid microhabitat, bulliform cells differentiated. Mesophyll was composed of cells of irregular shapes and resembled aerenchyma. The ultrastructural observations of mesophyll in all plants showed tight adherence of chloroplasts, mitochondria and peroxisomes, surface deformations of these organelles and formation of characteristic outgrowths and pocket concavities filled with cytoplasm with vesicles and organelles by chloroplasts. In reproduction biology of examined Caryophyllaceae and Poaceae plants growing in natural conditions, in the Arctic and in the Antarctic, and in a greenhouse in Olsztyn showed that this plant develops two types of bisexual flowers. Almost all ovules developed and formed seeds with a completely differentiated embryo both under natural conditions in the Arctic and the Antarctic and in a greenhouse in Olsztyn.

  2. Composition, buoyancy regulation and fate of ice algal aggregates in the Central Arctic Ocean.

    PubMed

    Fernández-Méndez, Mar; Wenzhöfer, Frank; Peeken, Ilka; Sørensen, Heidi L; Glud, Ronnie N; Boetius, Antje

    2014-01-01

    Sea-ice diatoms are known to accumulate in large aggregates in and under sea ice and in melt ponds. There is recent evidence from the Arctic that such aggregates can contribute substantially to particle export when sinking from the ice. The role and regulation of microbial aggregation in the highly seasonal, nutrient- and light-limited Arctic sea-ice ecosystem is not well understood. To elucidate the mechanisms controlling the formation and export of algal aggregates from sea ice, we investigated samples taken in late summer 2011 and 2012, during two cruises to the Eurasian Basin of the Central Arctic Ocean. Spherical aggregates densely packed with pennate diatoms, as well as filamentous aggregates formed by Melosira arctica showed sign of different stages of degradation and physiological stoichiometries, with carbon to chlorophyll a ratios ranging from 110 to 66700, and carbon to nitrogen molar ratios of 8-35 and 9-40, respectively. Sub-ice algal aggregate densities ranged between 1 and 17 aggregates m(-2), maintaining an estimated net primary production of 0.4-40 mg C m(-2) d(-1), and accounted for 3-80% of total phototrophic biomass and up to 94% of local net primary production. A potential factor controlling the buoyancy of the aggregates was light intensity, regulating photosynthetic oxygen production and the amount of gas bubbles trapped within the mucous matrix, even at low ambient nutrient concentrations. Our data-set was used to evaluate the distribution and importance of Arctic algal aggregates as carbon source for pelagic and benthic communities.

  3. Composition, Buoyancy Regulation and Fate of Ice Algal Aggregates in the Central Arctic Ocean

    PubMed Central

    Fernández-Méndez, Mar; Wenzhöfer, Frank; Peeken, Ilka; Sørensen, Heidi L.; Glud, Ronnie N.; Boetius, Antje

    2014-01-01

    Sea-ice diatoms are known to accumulate in large aggregates in and under sea ice and in melt ponds. There is recent evidence from the Arctic that such aggregates can contribute substantially to particle export when sinking from the ice. The role and regulation of microbial aggregation in the highly seasonal, nutrient- and light-limited Arctic sea-ice ecosystem is not well understood. To elucidate the mechanisms controlling the formation and export of algal aggregates from sea ice, we investigated samples taken in late summer 2011 and 2012, during two cruises to the Eurasian Basin of the Central Arctic Ocean. Spherical aggregates densely packed with pennate diatoms, as well as filamentous aggregates formed by Melosira arctica showed sign of different stages of degradation and physiological stoichiometries, with carbon to chlorophyll a ratios ranging from 110 to 66700, and carbon to nitrogen molar ratios of 8–35 and 9–40, respectively. Sub-ice algal aggregate densities ranged between 1 and 17 aggregates m−2, maintaining an estimated net primary production of 0.4–40 mg C m−2 d−1, and accounted for 3–80% of total phototrophic biomass and up to 94% of local net primary production. A potential factor controlling the buoyancy of the aggregates was light intensity, regulating photosynthetic oxygen production and the amount of gas bubbles trapped within the mucous matrix, even at low ambient nutrient concentrations. Our data-set was used to evaluate the distribution and importance of Arctic algal aggregates as carbon source for pelagic and benthic communities. PMID:25208058

  4. ER-2 #809 receives preflight fueling outside Arena Arctica hangar in Kiruna, Sweden prior to the SAGE III Ozone Loss and Validation Experiment (SOLVE)

    NASA Image and Video Library

    2000-01-24

    ER-2s bearing tail numbers 806 and 809 are used as airborne science platforms by NASA's Dryden Flight Research Center. The aircraft are platforms for a variety of high-altitude science missions flown over various parts of the world. They are also used for earth science and atmospheric sensor research and development, satellite calibration and data validation. The ER-2s are capable of carrying a maximum payload of 2,600 pounds of experiments in a nose bay, the main equipment bay behind the cockpit, two wing-mounted superpods and small underbody and trailing edges. Most ER-2 missions last about six hours with ranges of about 2,200 nautical miles. The aircraft typically fly at altitudes above 65,000 feet. On November 19, 1998, an ER-2 set a world record for medium weight aircraft reaching an altitude of 68,700 feet. The aircraft is 63 feet long, with a wingspan of 104 feet. The top of the vertical tail is 16 feet above ground when the aircraft is on the bicycle-type landing gear. Cruising speeds are 410 knots, or 467 miles per hour, at altitude. A single General Electric F-118 turbofan engine rated at 17,000 pounds thrust powers the ER-2.

  5. Environmental effects monitoring at the Terra Nova offshore oil development (Newfoundland, Canada): Program design and overview

    NASA Astrophysics Data System (ADS)

    DeBlois, Elisabeth M.; Tracy, Ellen; Janes, G. Gregory; Crowley, Roger D.; Wells, Trudy A.; Williams, Urban P.; Paine, Michael D.; Mathieu, Anne; Kilgour, Bruce W.

    2014-12-01

    An environmental effects monitoring (EEM) program was developed by Suncor (formerly Petro-Canada) in 1997/98 to assess effects of the Terra Nova offshore oil and gas development on the receiving environment. The Terra Nova Field is located on the Grand Banks approximately 350 km southeast of Newfoundland (Canada), at approximately 100 m water depth. The EEM program was developed with guidance from experts in government, academia and elsewhere, and with input from the public. The EEM program proposed by Suncor was accepted by Canadian regulatory agencies and the program was implemented in 2000, 2001, 2002, 2004, 2006, 2008 and 2010, with pre-development sampling in 1997. The program continues to be implemented every two years. EEM includes an assessment of alterations in sediment quality through examination of changes in sediment chemistry, particle size, toxicity and benthic invertebrate community structure. A second component of the program examines potential effects on two species of commercial fishing interest: Iceland scallop (Chlamys islandica) and American plaice (Hippoglossoides platessoides). Chemical body burden for these two species is examined and taste tests are performed to assess the presence of taint in edible tissues. Effects on American plaice bioindicators are also examined. A final component of the program assesses potential effects of the Terra Nova development on water quality and examines water column chemistry, chlorophyll concentration and physical properties. The papers presented in this collection focus on effects of drill cuttings and drilling muds on the seafloor environment and, as such, report results on sediment quality and bioaccumulation of drilling mud components in Iceland scallop and American plaice. This paper provides information on drilling discharges, an overview of the physical oceanography at the Terra Nova Field, and an overview of the field program designed to assess environmental effects of drilling at Terra Nova.

  6. Cooperation, conflict, and crèching behavior in goldeneye ducks.

    PubMed

    Eadie, J M; Lyon, B E

    1998-05-01

    Crèching behavior, or brood amalgamation, results in offspring being reared by adults other than their genetic parents. Although a variety of hypotheses have been proposed to explain this behavior, most assume either that brood amalgamation is accidental (i.e., nonselected) or that adoption of young is selected for because of social benefits to the young and/or adopting parents. We propose, instead, that brood amalgamation is a function of two separate processes: brood desertion and brood adoption. To examine brood desertion, we develop a graphic model to predict when parents should abandon their young and we test this model experimentally for the Barrow's goldeneye (Bucephala islandica). As predicted, females deserted their offspring when the size of the brood was experimentally reduced. Brood adoption occurred when deserted ducklings joined other broods. However, the success of ducklings in doing so was strongly dependent on the availability of potential host broods and on the age of the recipient broods. Foreign ducklings were readily accepted into young broods (<10 d old) but invariably were rejected from old broods. We could detect no benefits or costs of brood adoption to the host females, contrary to the expectations of a social benefit hypothesis. Our experiments indicate that Crèching behavior is driven by selection on adults to abandon their brood when the benefits of continued investment are outweighed by the reduction in future reproduction and selection on deserted ducklings to join other broods to obtain parental care. Rather than a form of cooperative brood care, Crèching in goldeneyes is perhaps best considered as a form of reproductive parasitism, entailing parent-offspring conflict over brood desertion and intergenerational conflict over adoption of abandoned young.

  7. When the seasons don't fit: speedy molt as a routine carry-over cost of reproduction.

    PubMed

    Dietz, Maurine W; Rogers, Ken G; Piersma, Theunis

    2013-01-01

    The failure of animals to fit all life-cycle stages into an annual cycle could reduce the chances of successful breeding. In some cases, non-optimal strategies will be adopted in order to maintain the life-cycle within the scope of one year. We studied trade-offs made by a High Arctic migrant shorebird, the red knot Calidris canutus islandica, between reproduction and wing feather molt carried out in the non-breeding period in the Dutch Wadden Sea. We compared primary molt duration between birds undertaking the full migratory and breeding schedule with birds that forego breeding because they are young or are maintained in captivity. Molt duration was ca. 71 days in breeding adults, which was achieved by an accelerated feather replacement strategy. Second-year birds and captive adults took ca. 22% and 27% longer, respectively. Second-year birds start molt in late June, more than four weeks before captive adults, and almost seven weeks before adults that return from breeding in late July-August. Adults finish molt in October when steeply increasing thermostatic costs and reductions in food availability occur. Primary molt duration was longer in female than in male knots (all ages), which was accordance with the somewhat larger body size of females. Since fast growth leads to lower quality feathers, the speedy wing molt shown by Arctic-breeding birds may represent a time constraint that is an unavoidable and routine cost of reproduction. So far it was hypothesized that only birds over 1 kg would have difficulty fitting molt within a year. Here we show that in birds an order of magnitude smaller, temporal imperatives may impose the adoption of non-optimal life-cycle routines in the entire actively breeding population.

  8. Nitrotoga-like bacteria are previously unrecognized key nitrite oxidizers in full-scale wastewater treatment plants.

    PubMed

    Lücker, Sebastian; Schwarz, Jasmin; Gruber-Dorninger, Christiane; Spieck, Eva; Wagner, Michael; Daims, Holger

    2015-03-01

    Numerous past studies have shown members of the genus Nitrospira to be the predominant nitrite-oxidizing bacteria (NOB) in nitrifying wastewater treatment plants (WWTPs). Only recently, the novel NOB 'Candidatus Nitrotoga arctica' was identified in permafrost soil and a close relative was enriched from activated sludge. Still, little is known about diversity, distribution and functional importance of Nitrotoga in natural and engineered ecosystems. Here we developed Nitrotoga 16S rRNA-specific PCR primers and fluorescence in situ hybridization (FISH) probes, which were applied to screen activated sludge samples from 20 full-scale WWTPs. Nitrotoga-like bacteria were detected by PCR in 11 samples and reached abundances detectable by FISH in seven sludges. They coexisted with Nitrospira in most of these WWTPs, but constituted the only detectable NOB in two systems. Quantitative FISH revealed that Nitrotoga accounted for nearly 2% of the total bacterial community in one of these plants, a number comparable to Nitrospira abundances in other WWTPs. Spatial statistics revealed that Nitrotoga coaggregated with ammonia-oxidizing bacteria, strongly supporting a functional role in nitrite oxidation. This activity was confirmed by FISH in combination with microradiography, which revealed nitrite-dependent autotrophic carbon fixation by Nitrotoga in situ. Correlation of the presence or absence with WWTP operational parameters indicated low temperatures as a main factor supporting high Nitrotoga abundances, although in incubation experiments these NOB remained active over an unexpected range of temperatures, and also at different ambient nitrite concentrations. In conclusion, this study demonstrates that Nitrotoga can be functionally important nitrite oxidizers in WWTPs and can even represent the only known NOB in engineered systems.

  9. Phylogenetic relationships within the Alcidae (Charadriiformes: Aves) inferred from total molecular evidence

    USGS Publications Warehouse

    Friesen, Vicki L.; Baker, Allan J.; Piatt, John F.

    1996-01-01

    The Alcidae is a unique assemblage of Northern Hemisphere seabirds that forage by "flying" underwater. Despite obvious affinities among the species, their evolutionary relationships are unclear. We analyzed nucleotide sequences of 1,045 base pairs of the mitochondrial cytochrome b gene and allelic profiles for 37 allozyme loci in all 22 extant species. Trees were constructed on independent and combined data sets using maximum parsimony and distance methods that correct for superimposed changes. Alternative methods of analysis produced only minor differences in relationships that were supported strongly by bootstrapping or standard error tests. Combining sequence and allozyme data into a single analysis provided the greatest number of relationships receiving strong support. Addition of published morphological and ecological data did not improve support for any additional relationship. All analyses grouped species into six distinct lineages: (1) the dovekie (Alle alle) and auks, (2) guillemots, (3) brachyramphine murrelets, (4) synthliboramphine murrelets, (5) true auklets, and (6) the rhinoceros auklet (Cerorhinca monocerata) and puffins. The two murres (genus Uria) were sister taxa, and the black guillemot (Cepphus grylle) was basal to the other guillemots. The Asian subspecies of the marbled murrelet (Brachyramphus marmoratus perdix) was the most divergent brachyramphine murrelet, and two distinct lineages occurred within the synthliboramphine murrelets. Cassin's auklet (Ptychoramphus aleuticus) and the rhinoceros auklet were basal to the other auklets and puffins, respectively, and the Atlantic (Fratercula arctica) and horned (Fratercula corniculata) puffins were sister taxa. Several relationships among tribes, among the dovekie and auks, and among the auklets could not be resolved but resembled "star" phylogenies indicative of adaptive radiations at different depths within the trees.

  10. Sterol and genomic analyses validate the sponge biomarker hypothesis

    PubMed Central

    Gold, David A.; Grabenstatter, Jonathan; de Mendoza, Alex; Riesgo, Ana; Ruiz-Trillo, Iñaki

    2016-01-01

    Molecular fossils (or biomarkers) are key to unraveling the deep history of eukaryotes, especially in the absence of traditional fossils. In this regard, the sterane 24-isopropylcholestane has been proposed as a molecular fossil for sponges, and could represent the oldest evidence for animal life. The sterane is found in rocks ∼650–540 million y old, and its sterol precursor (24-isopropylcholesterol, or 24-ipc) is synthesized today by certain sea sponges. However, 24-ipc is also produced in trace amounts by distantly related pelagophyte algae, whereas only a few close relatives of sponges have been assayed for sterols. In this study, we analyzed the sterol and gene repertoires of four taxa (Salpingoeca rosetta, Capsaspora owczarzaki, Sphaeroforma arctica, and Creolimax fragrantissima), which collectively represent the major living animal outgroups. We discovered that all four taxa lack C30 sterols, including 24-ipc. By building phylogenetic trees for key enzymes in 24-ipc biosynthesis, we identified a candidate gene (carbon-24/28 sterol methyltransferase, or SMT) responsible for 24-ipc production. Our results suggest that pelagophytes and sponges independently evolved C30 sterol biosynthesis through clade-specific SMT duplications. Using a molecular clock approach, we demonstrate that the relevant sponge SMT duplication event overlapped with the appearance of 24-isopropylcholestanes in the Neoproterozoic, but that the algal SMT duplication event occurred later in the Phanerozoic. Subsequently, pelagophyte algae and their relatives are an unlikely alternative to sponges as a source of Neoproterozoic 24-isopropylcholestanes, consistent with growing evidence that sponges evolved long before the Cambrian explosion ∼542 million y ago. PMID:26903629

  11. Diminishing sea ice in the western Arctic Ocean

    USGS Publications Warehouse

    Stone, R.S.; Belchansky, G.I.; Drobot, Sheldon; Douglas, David C.; Levinson, D.H.; Waple, A.M.

    2004-01-01

    Since the advent of satellite passive microwave radiometry (1978), variations in sea ice extent and concentration have been carefully monitored from space. An estimated 7.4% decrease in sea ice extent has occurred in the last 25 yr (Johannessen et al. 2004), with recent record minima (e.g., Maslanik et al. 1999; Serreze et al. 2003) accounting for much of the decline. Comparisons between the time series of Arctic sea ice melt dynamics and snowmelt dates at the NOAA–CMDL Barrow Observatory (BRW) reveal intriguing correlations.Melt-onset dates over sea ice (Drobot and Anderson 2001) were cross correlated with the melt-date time series from BRW, and a prominent region of high correlation between snowmelt onset over sea ice and the BRW record of melt dates was approximately aligned with the climatological center of the Beaufort Sea Anticyclone (BSA). The BSA induces anticyclonic ice motion in the region, effectively forcing the Beaufort gyre. A weak gyre caused by a breakdown of the BSA diminishes transport of multiyear ice into this region (Drobot and Maslanik 2003). Similarly, the annual snow cycle at BRW varies with the position and intensity of the BSA (Stone et al. 2002, their Fig. 6). Thus, variations in the BSA appear to have far-reaching effects on the annual accumulation and subsequent melt of snow over a large region of the western Arctic.A dramatic increase in melt season duration (Belchansky et al. 2004) was also observed within the same region of high correlation between onset of melt over the ice pack and snowmelt at BRW (Fig. 5.7). By inference, this suggests linkages between factors that modulate the annual cycle of snow on land and processes that influence melting of snow and ice in the western Arctic Ocean.

  12. The Bering Land Bridge: a moisture barrier to the dispersal of steppe-tundra biota?

    NASA Astrophysics Data System (ADS)

    Elias, Scott A.; Crocker, Barnaby

    2008-12-01

    The Bering Land Bridge (BLB) connected the two principal arctic biological refugia, Western and Eastern Beringia, during intervals of lowered sea level in the Pleistocene. Fossil evidence from lowland BLB organic deposits dating to the Last Glaciation indicates that this broad region was dominated by shrub tundra vegetation, and had a mesic climate. The dominant ecosystem in Western Beringia and the interior regions of Eastern Beringia was steppe-tundra, with herbaceous plant communities and arid climate. Although Western and Eastern Beringia shared many species in common during the Late Pleistocene, there were a number of species that were restricted to only one side of the BLB. Among the vertebrate fauna, the woolly rhinoceros was found only to the west of the BLB, North American camels, bonnet-horned musk-oxen and some horse species were found only to the east of the land bridge. These were all steppe-tundra inhabitants, adapted to grazing. The same phenomenon can be seen in the insect faunas of the Western and Eastern Beringia. The steppe-tundra beetle fauna of Western Beringia was dominated by weevils of the genus Stephanocleonus, a group that was virtually absent from Eastern Beringia. The dry-adapted weevils, Lepidophorus lineaticollis and Vitavitus thulius were important members of steppe-tundra communities in Eastern Beringia, but were either absent or rare in Western Beringia. The leaf beetles Chrysolina arctica, C. brunnicornis bermani, and Galeruca interrupta circumdata were typical members of the Pleistocene steppe-tundra communities of Western Beringia, but absent from Eastern Beringia. On the other hand, some steppe tundra-adapted leaf beetles managed to occupy both sides of the BLB, such as Phaedon armoraciae. Much of the BLB remains unstudied, but on biogeographic grounds, it appears that there was some kind of biological filter that blocked the movements of some steppe-tundra plants and animals across the BLB.

  13. Diel Variation of Biogenic Volatile Organic Compound Emissions- A field Study in the Sub, Low and High Arctic on the Effect of Temperature and Light

    PubMed Central

    Lindwall, Frida; Faubert, Patrick; Rinnan, Riikka

    2015-01-01

    Many hours of sunlight in the midnight sun period suggest that significant amounts of biogenic volatile organic compounds (BVOCs) may be released from arctic ecosystems during night-time. However, the emissions from these ecosystems are rarely studied and limited to point measurements during daytime. We measured BVOC emissions during 24-hour periods in the field using a push-pull chamber technique and collection of volatiles in adsorbent cartridges followed by analysis with gas chromatography- mass spectrometry. Five different arctic vegetation communities were examined: high arctic heaths dominated by Salix arctica and Cassiope tetragona, low arctic heaths dominated by Salix glauca and Betula nana and a subarctic peatland dominated by the moss Warnstorfia exannulata and the sedge Eriophorum russeolum. We also addressed how climate warming affects the 24-hour emission and how the daytime emissions respond to sudden darkness. The emissions from the high arctic sites were lowest and had a strong diel variation with almost no emissions during night-time. The low arctic sites as well as the subarctic site had a more stable release of BVOCs during the 24-hour period with night-time emissions in the same range as those during the day. These results warn against overlooking the night period when considering arctic emissions. During the day, the quantity of BVOCs and the number of different compounds emitted was higher under ambient light than in darkness. The monoterpenes α-fenchene, α -phellandrene, 3-carene and α-terpinene as well as isoprene were absent in dark measurements during the day. Warming by open top chambers increased the emission rates both in the high and low arctic sites, forewarning higher emissions in a future warmer climate in the Arctic. PMID:25897519

  14. Sea spray as a source of ice nucleating particles - results from the AIDA Ocean03 campaign

    NASA Astrophysics Data System (ADS)

    Salter, M. E.; Ickes, L.; Adams, M.; Bierbauer, S.; Bilde, M.; Christiansen, S.; Ekman, A.; Gorokhova, E.; Höhler, K.; Kiselev, A. A.; Leck, C.; Mohr, C.; Mohler, O.; Murray, B. J.; Porter, G.; Ullrich, R.; Wagner, R.

    2017-12-01

    Clouds and their radiative effects are one of the major influences on the radiative fluxes in the atmosphere, but at the same time they remain the largest uncertainty in climate models. This lack of understanding is especially pronounced in the high Arctic. Summertime clouds can persist over long periods in this region, which is difficult to replicate in models based on our current understanding. The clouds most often encountered in the summertime high Arctic consist of a mixture of ice crystals and super-cooled water droplets, so-called mixed-phase clouds. This cloud type is sensitive to the availability of aerosol particles, which can act as cloud condensation nuclei and ice nuclei. However, since the high Arctic is a pristine region, aerosol particles are not very abundant, and the hypothesis of open leads in the Arctic as a potentially important source of cloud and ice nucleating particles via bubble bursting has emerged. In this context, we have conducted a series of experiments at the AIDA chamber at KIT, designed to investigate the mechanisms linking marine biology, seawater chemistry and aerosol physics/potential cloud impacts. During this campaign, two marine diatom species (Melosira arctica and Skeletonema marinoi) as well as sea surface microlayer samples collected during several Arctic Ocean research cruises were investigated. To aerosolize the samples, a variety of methods were used including a sea spray simulation chamber to mimic the process of bubble-bursting. The ice nucleating efficiency (mixed-phase cloud regime) of the samples was determined either directly in the AIDA chamber during adiabatic expansions, or using the INKA continuous flow diffusion chamber, or a cold stage. Results from the campaign along with the potential implications are presented.

  15. Arctic ground squirrels of the mammoth-steppe: paleoecology of Late Pleistocene middens (˜24 000 29 450 14C yr BP), Yukon Territory, Canada

    NASA Astrophysics Data System (ADS)

    Zazula, Grant D.; Froese, Duane G.; Elias, Scott A.; Kuzmina, Svetlana; Mathewes, Rolf W.

    2007-04-01

    This paper presents paleoecological analyses of 48 fossil arctic ground squirrel ( Spermophilus parryii) middens (nests and caches) recovered from ice-rich loess sediments in the Klondike region of west-central Yukon Territory. AMS radiocarbon dates and stratigraphic association of middens with Dawson tephra (˜25 300 14C yr BP), indicate these paleoecological data reflect the onset of glacial conditions of early Marine Isotope Stage (MIS) 2 and terminal MIS 3 (˜24 000-29 450 14C yr BP). Plant macrofossils include at least 60 plant taxa, including diverse graminoids ( Poa, Elymus trachycaulus, Kobresia myosuroides), steppe forbs ( Penstemon gormanii, Anemone patens var. multifida, Plantago cf. canescens), tundra forbs ( Draba spp., Bistorta vivipara), dwarf shrubs ( Salix cf. arctica, S. cf. polaris), sage ( Artemisia frigida) and rare trees ( Picea mariana). Many of these taxa identified in the middens represent the first recorded fossils for these plants in Eastern Beringia and add to our knowledge of the floristic composition of Pleistocene vegetation and biogeography in this region. Fossil beetles include typical members of the Eastern Beringian steppe-tundra fauna ( Lepidophorus lineaticollis and Connatichela artemisiae) and others suggesting predominantly dry, open habitats. Cache forage selection is suggested by some plant taxa which were particularly frequent and abundant in the middens ( Bistorta vivipara, Kobresia myosuroides, Ranunculus spp., Potentilla, Erysimum cf. cheiranthoides, Poa, Carex and Draba). Factors such as proximity of vegetation to burrows and abundance of fruits and seeds per plant were probably important in cache selection. Glacial conditions enabled arctic ground squirrels to form widespread and dense populations in regions such as the Klondike in which they are rare or absent at present. This fossil midden record supports previous hypotheses that suggest arctic ground squirrels evolved in and are well-adapted to the open, steppe

  16. From Puffins to Plankton: A DNA-Based Analysis of a Seabird Food Chain in the Northern Gulf of Maine

    PubMed Central

    Bowser, A. Kirsten; Diamond, Antony W.; Addison, Jason A.

    2013-01-01

    The predator-prey interactions within food chains are used to both characterize and understand ecosystems. Conventional methods of constructing food chains from visual identification of prey in predator diet can suffer from poor taxonomic resolution, misidentification, and bias against small or completely digestible prey. Next-generation sequencing (NGS) technology has become a powerful tool for diet reconstruction through barcoding of DNA in stomach content or fecal samples. Here we use multi-locus (16S and CO1) next-generation sequencing of DNA barcodes on the feces of Atlantic puffin (Fratercula arctica) chicks (n=65) and adults (n=64) and the stomach contents of their main prey, Atlantic herring (Clupea harengus, n=44) to investigate a previously studied food chain. We compared conventional and molecular-derived chick diet, tested the similarity between the diets of puffin adults and chicks, and determined whether herring prey can be detected in puffin diet samples. There was high variability in the coverage of prey groups between 16S and CO1 markers. We identified more unique prey with our 16S compared to CO1 barcoding markers (51 and 39 taxa respectively) with only 12 taxa identified by both genes. We found no significant difference between the 16S-identified diets of puffin adults (n=17) and chicks (n=41). Our molecular method is more taxonomically resolved and detected chick prey at higher frequencies than conventional field observations. Many likely planktonic prey of herring were detected in feces from puffin adults and chicks, highlighting the impact secondary consumption may have on the interpretation of molecular dietary analysis. This study represents the first simultaneous molecular investigation into the diet of multiple components of a food chain and highlights the utility of a multi-locus approach to diet reconstruction that is broadly applicable to food web analysis. PMID:24358258

  17. Myxozoa in high Arctic: Survey on the central part of Svalbard archipelago

    PubMed Central

    Kodádková, Alena; Dyková, Iva; Tyml, Tomáš; Ditrich, Oleg; Fiala, Ivan

    2014-01-01

    Myxosporeans (Myxozoa), microscopic metazoan parasitic organisms, are poorly studied in the Arctic region. Our survey of benthic and pelagic fish (n = 234) collected in Isfjorden (Svalbard, Norway) together with detailed morphological and molecular examination revealed the presence of nine myxosporean species. We compared observed myxosporean diversity with diversity documented in regions close to the Arctic and revealed that water depth rather than geographic distribution is an important factor influencing myxosporean fauna. We describe three new myxosporean species: Zschokkella siegfriedi n. sp. from kidney of Boreogadus saida, Parvicapsula petuniae n. sp. from the urinary bladder of Gymnocanthus tricuspis, and Sinuolinea arctica n. sp. from the urinary bladder of Myoxocephalus scorpius. We characterise Latyspora-like organism from kidney of Clupea harengus. We provide new data for Ceratomyxa porrecta, Myxidium gadi, Myxidium finnmarchicum, Schulmania aenigmatosa, and Parvicapsula irregularis comb. nov. The phylogenetic analyses including the newly obtained SSU and LSU rDNA data revealed that most of the species studied cluster in the marine urinary clade within the marine myxosporean lineage. Newly obtained sequences including the first molecular data for the member of the genus Schulmania, substantially enriched the Zschokkella subclade. C. porrecta and the two Myxidium species cluster within the Ceratomyxa and marine Myxidium clade, respectively. Newly described species, Z. siegfriedi n. sp., was revealed to be morphologically indistinguishable but genetically diverse from Zschokkella hildae known from numerous gadid fish. Therefore, we consider Z. siegfriedi to be a cryptic myxosporean species that might be misidentified with Z. hildae. A Latyspora-like organism was found to be taxonomically problematic due to its suture line and its distant phylogenetic position from the type species Latyspora scomberomori did not allow us to assign it to the genus

  18. Quaternary ostracode and foraminiferal biostratigraphy and paleoceanography in the western Arctic Ocean

    USGS Publications Warehouse

    Cronin, Thomas M.; DeNinno, Lauren H.; Polyak, L.V.; Caverly, Emma K.; Poore, Richard; Brenner, Alec R.; Rodriguez-Lazaro, J.; Marzen, R.E.

    2014-01-01

    The stratigraphic distributions of ostracodes and selected calcareous benthic and planktic foraminiferal species were studied in sediment cores from ~ 700 to 2700 m water depth on the Northwind, Mendeleev, and Lomonosov Ridges in the western Arctic Ocean. Microfaunal records in most cores cover mid- to late Quaternary sediments deposited in the last ~ 600 ka, with one record covering the last ~ 1.5 Ma. Results show a progressive faunal turnover during the mid-Pleistocene transition (MPT, ~ 1.2 to 0.7 Ma) and around the mid-Brunhes event (MBE, ~ 0.4 Ma) reflecting major changes in Arctic Ocean temperature, circulation and sea-ice cover. The observed MPT shift is characterized by the extinction of species that today inhabit the sea-ice free subpolar North Atlantic and/or seasonally sea-ice free Nordic Seas (Echinocythereis sp., Rockalliacf. enigmatica, Krithe cf. aquilonia, Pterygocythereis vannieuwenhuisei). After a very warm interglacial during marine isotope stage (MIS) 11 dominated by the temperate planktic foraminifer Turborotalita egelida, the MBE experienced a shift to polar assemblages characteristic of predominantly perennial Arctic sea-ice cover during the interglacial and interstadial periods of the last 300 ka. These include the planktic foraminifera Neogloboquadrina pachyderma, the sea-ice dwelling ostracodeAcetabulastoma arcticum and associated benthic taxa Pseudocythere caudata,Pedicythere neofluitans, and Polycope spp. Several species can be used as biostratigraphic markers of specific intervals such as ostracodes Rabilimis mirabilis — MIS 5 and P. vannieuwenhuisei extinction after MIS 11, and foraminiferal abundance zones Bulimina aculeata — late MIS 5 and Bolivina arctica — MIS 5-11.

  19. In vitro neuroprotective potential of lichen metabolite fumarprotocetraric acid via intracellular redox modulation

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Fernández-Moriano, Carlos

    2017-02-01

    The lichen-forming fungi Cetraria islandica has been largely used in folk medicines, and it has recently showed promising in vitro antioxidant effects in glial-like cells. Current work aimed at investigating the neuroprotective potential of its major isolated secondary metabolite: the depsidone fumarprotocetraric acid (FUM). H{sub 2}O{sub 2} was used herein to induce oxidative stress (OS)-mediated cytotoxicity in two models of neurons and astrocytes cells (SH-SY5Y and U373-MG cell lines). We found that a pre-treatment with FUM significantly enhanced cell viability compared to H{sub 2}O{sub 2}-treated cells, and we selected the optimal concentrations in each model (1 and 25 μg/ml, respectively)more » for assessing its cytoprotective mechanisms. FUM, which exerted effective peroxyl radical scavenging effect in the chemical oxygen radical antioxidant capacity (ORAC) assay, alleviated the alterations in OS markers provoked by H{sub 2}O{sub 2}. It attenuated intracellular ROS formation, lipid peroxidation and GSH depletion. At mitochondrial level, FUM prevented from the dissipation of mitochondrial membrane potential and the increase in mitochondrial calcium, implying a protective role against oxidative damage in mitochondrial membrane. Similarly, FUM pre-treatment diminished H{sub 2}O{sub 2}-induced apoptosis, as evidenced by the reduction in caspase-3 activity and expression; inmunoblot analysis also revealed a decrease in Bax and an increase in Bcl-2 proteins levels. Furthermore, FUM up-regulated the expression of the antioxidant enzymes catalase, superoxide dismutase-1, and hemeoxigenase-1. These findings and the activation of Nrf2 binding activity in nuclear extracts suggest a plausible involvement of Nrf2 signaling pathway in the cytoprotection by FUM. In conclusion, FUM emerges as a potential drug candidate in the therapy of OS-related diseases, such as the neurodegenerative disorders. - Highlights: • FUM pre-treatment exerts significant cytoprotection

  20. Spectral properties of subarctic plants for remote ecosystem assessment

    NASA Astrophysics Data System (ADS)

    Golubeva, Elena; Tutubalina, Olga; Rees, Gareth; Zimin, Mikhail; Mikheeva, Anna

    2014-05-01

    Multispectral and hyperspectral satellite images are increasingly used to identify properties of vegetation, its state, dynamics and productivity. Arctic vegetation is sensitive to changing habitat conditions related to both natural causes (in particular climatic trends), and human impact (both direct and indirect, e.g. associated with air, soil and water pollution). Change in the state of individual plants and of vegetation cover in general enables their use as indicators of natural and anthropogenic processes, manifested in satellite images through change of their spectral reflectance properties. These processes can be studied by identifying significant links between spectral properties of objects in satellite images and corresponding properties of plants, recorded in situ. We focus on the spectral signatures of subarctic plants dominating treeline ecotone ecosystems to assess the feasibility of mapping the spatial structure and dynamics of vegetation using multispectral and hyperspectral satellite imagery. Our model objects are tundra plants and ecosystems in both natural and technogenically disturbed environments in the central part of the Kola Peninsula, Russia. We conducted ground spectroradiometry with two spectroradiometers: ASD FieldSpec 3 Hi-res (350-2500 nm range with resolution from 3 to 10 nm) and SkyeInstruments SpectroSense 2+ (bands centred at 480, 550, 680, 840 nm, 50-130 nm wide) for samples of different species: Betula pubescens S.L., B. tortuosa, Picea abies, Betula nana, Ledum palustre, Vaccinium uligimosum, V. myrtillus, V. vitis-idaea, Empetrum hermaphroditum, Cetraria islandica (L), Flavocetraria nivalis (Cetraria nivalis), Alectoria ochroleuca, Cladonia arbuscula S.L., Hylocomium splendens and Pleurozium Shreberi. The results demonstrate the ability of green vegetation to selectively reflect solar radiation, depending on the species composition and state of the plants. Our results will be included in a spectral library of northern plants

  1. Highly pathogenic avian influenza virus H5N1 infection in a long-distance migrant shorebird under migratory and non-migratory states.

    PubMed

    Reperant, Leslie A; van de Bildt, Marco W G; van Amerongen, Geert; Buehler, Debbie M; Osterhaus, Albert D M E; Jenni-Eiermann, Susi; Piersma, Theunis; Kuiken, Thijs

    2011-01-01

    Corticosterone regulates physiological changes preparing wild birds for migration. It also modulates the immune system and may lead to increased susceptibility to infection, with implications for the spread of pathogens, including highly pathogenic avian influenza virus (HPAIV) H5N1. The red knot (Calidris canutus islandica) displays migratory changes in captivity and was used as a model to assess the effect of high plasma concentration of corticosterone on HPAIV H5N1 infection. We inoculated knots during pre-migration (N = 6), fueling (N = 5), migration (N = 9) and post-migration periods (N = 6). Knots from all groups shed similar viral titers for up to 5 days post-inoculation (dpi), peaking at 1 to 3 dpi. Lesions of acute encephalitis, associated with virus replication in neurons, were seen in 1 to 2 knots per group, leading to neurological disease and death at 5 to 11 dpi. Therefore, the risk of HPAIV H5N1 infection in wild birds and of potential transmission between wild birds and poultry may be similar at different times of the year, irrespective of wild birds' migratory status. However, in knots inoculated during the migration period, viral shedding levels positively correlated with pre-inoculation plasma concentration of corticosterone. Of these, knots that did not become productively infected had lower plasma concentration of corticosterone. Conversely, elevated plasma concentration of corticosterone did not result in an increased probability to develop clinical disease. These results suggest that birds with elevated plasma concentration of corticosterone at the time of migration (ready to migrate) may be more susceptible to acquisition of infection and shed higher viral titers--before the onset of clinical disease--than birds with low concentration of corticosterone (not ready for take-off). Yet, they may not be more prone to the development of clinical disease. Therefore, assuming no effect of sub-clinical infection on the likelihood of

  2. Complex carbon cycle responses to multi-level warming and supplemental summer rain in the high Arctic.

    PubMed

    Sharp, Elizabeth D; Sullivan, Patrick F; Steltzer, Heidi; Csank, Adam Z; Welker, Jeffrey M

    2013-06-01

    The Arctic has experienced rapid warming and, although there are uncertainties, increases in precipitation are projected to accompany future warming. Climate changes are expected to affect magnitudes of gross ecosystem photosynthesis (GEP), ecosystem respiration (ER) and the net ecosystem exchange of CO2 (NEE). Furthermore, ecosystem responses to climate change are likely to be characterized by nonlinearities, thresholds and interactions among system components and the driving variables. These complex interactions increase the difficulty of predicting responses to climate change and necessitate the use of manipulative experiments. In 2003, we established a long-term, multi-level and multi-factor climate change experiment in a polar semidesert in northwest Greenland. Two levels of heating (30 and 60 W m(-2) ) were applied and the higher level was combined with supplemental summer rain. We made plot-level measurements of CO2 exchange, plant community composition, foliar nitrogen concentrations, leaf δ(13) C and NDVI to examine responses to our treatments at ecosystem- and leaf-levels. We confronted simple models of GEP and ER with our data to test hypotheses regarding key drivers of CO2 exchange and to estimate growing season CO2 -C budgets. Low-level warming increased the magnitude of the ecosystem C sink. Meanwhile, high-level warming made the ecosystem a source of C to the atmosphere. When high-level warming was combined with increased summer rain, the ecosystem became a C sink of magnitude similar to that observed under low-level warming. Competition among our ER models revealed the importance of soil moisture as a driving variable, likely through its effects on microbial activity and nutrient cycling. Measurements of community composition and proxies for leaf-level physiology suggest GEP responses largely reflect changes in leaf area of Salix arctica, rather than changes in leaf-level physiology. Our findings indicate that the sign and magnitude of the future

  3. Endobiotic bacteria and their pathogenic potential in cnidarian tentacles

    NASA Astrophysics Data System (ADS)

    Schuett, Christian; Doepke, Hilke

    2010-09-01

    Endobiotic bacteria colonize the tentacles of cnidaria. This paper provides first insight into the bacterial spectrum and its potential of pathogenic activities inside four cnidarian species. Sample material originating from Scottish waters comprises the jellyfish species Cyanea capillata and C. lamarckii, hydrozoa Tubularia indivisa and sea anemone Sagartia elegans. Mixed cultures of endobiotic bacteria, pure cultures selected on basis of haemolysis, but also lyophilized samples were prepared from tentacles and used for DGGE-profiling with subsequent phylogenetic analysis of 16S rDNA fragments. Bacteria were detected in each of the cnidarian species tested. Twenty-one bacterial species including four groups of closely related organisms were found in culture material. The species within these groups could not be differentiated from each other (one group of Pseudoalteromonas spp., two groups of Shewanella spp., one group of Vibrio spp.). Each of the hosts exhibits a specific endobacterial spectrum. Solely Cyanea lamarckii harboured Moritella viscosa. Only in Cyanea capillata, members of the Shewanella group #2 and the species Pseudoalteromonas arctica, Shewanella violacea, Sulfitobacter pontiacus and Arcobacter butzleri were detected. Hydrozoa Tubularia indivisa provided an amazingly wide spectrum of nine bacterial species. Exclusively, in the sea anemone Sagartia elegans, the bacterial species P. aliena was found. Overall eleven bacterial species detected were described recently as novel species. Four 16S rDNA fragments generated from lyophilized material displayed extremely low relationship to their next neighbours. These organisms are regarded as members of the endobiotic “terra incognita”. Since the origin of cnidarian toxins is unclear, the possible pathogenic activity of endobiotic bacteria has to be taken into account. Literature data show that their next neighbours display an interesting diversity of haemolytic, septicaemic and necrotic actions including

  4. Sarcocystis caninum and Sarcocystis svanai n. spp. (Apicomplexa: Sarcocystidae) Associated with Severe Myositis and Hepatitis in the Domestic Dog (Canis familiaris)

    PubMed Central

    Dubey, J. P.; Sykes, J. E.; Shelton, G. D.; Sharp, N.; Verma, S. K.; Calero-Bernal, R.; Viviano, J.; Sundar, N.; Khan, A.; Grigg, M. E.

    2014-01-01

    There are several reports of Sarcocystis sarcocysts in muscles of dogs but these species have not been named. Additionally, there are 2 reports of Sarcocystis neurona in dogs. Here, we propose 2 new names, Sarcocystis caninum, and Sarcocystis svanai for sarcocysts associated with clinical muscular sarcocystosis in 4 domestic dogs (Canis familiaris), 1 each from Montana and Colorado in the USA, and 2 from British Columbia, Canada. Only the sarcocyst stage was identified. Most of the sarcocysts identified were S. caninum. Sarcocysts were studied using light microscopy, transmission electron microscopy, and PCR. Based on collective results 2 new species, Sarcocystis caninum and Sarcocystis svanai were designated. Sarcocystis caninum and Sarcocystis svanai were structurally distinct. Sarcocystis caninum sarcocysts were up to 1.2 mm long and up to 75 μm wide. By light microscopy, the sarcocyst wall was relatively thin and smooth. By transmission electron microscopy (TEM), the sarcocyst wall “type 9”, 1–2 μm thick, and contained villar protrusions that lacked microtubules. Bradyzoites in sections were 7–9 μm long. Sarcocysts of S. svanai were few and were identified by TEM. Sarcocystis svanai sarcocysts were “type 1”, thin walled (< 0.5 μm), and the wall lacked villar protrusions but had tiny blebs that did not invaginate. DNA was extracted either from infected frozen muscle biopsies or formalin-fixed paraffin-embedded sections. Dogs were either singly infected with S. caninum or multiply co-infected with S. caninum and S. svanai (the result of a mixed infection) based on multi-locus DNA sequencing and morphology. BLASTn analysis established that the sarcocysts identified in these dogs were similar to, but not identical to S. canis or S. arctosi, parasites found to infect polar bears (Ursus maritimus) or brown bears (Ursus arctosi), respectively. However, the S. caninum sequence showed 100% identify over the 18S rRNA region sequenced to that of S. arctica

  5. Isolated, but transnational: the glocal nature of Waldensian ethnobotany, Western Alps, NW Italy.

    PubMed

    Bellia, Giada; Pieroni, Andrea

    2015-05-07

    An ethnobotanical field study on the traditional uses of wild plants for food as well as medicinal and veterinary plants was conducted in four Waldensian valleys (Chisone, Germanasca, Angrogna, and Pellice) in the Western Alps, Piedmont, NW Italy. Waldensians represent a religious Protestant Christian minority that originated in France and spread around 1,170 AD to the Italian side of Western Alps, where, although persecuted for centuries, approximately 20,000 believers still survive today, increasingly mixing with their Catholic neighbours. Interviews with a total of 47 elderly informants, belonging to both Waldensian and Catholic religious groups, were undertaken in ten Western Alpine villages, using standard ethnobotanical methods. The uses of 85 wild and semi-domesticated food folk taxa, 96 medicinal folk taxa, and 45 veterinary folk taxa were recorded. Comparison of the collected data within the two religious communities shows that Waldensians had, or have retained, a more extensive ethnobotanical knowledge, and that approximately only half of the wild food and medicinal plants are known and used by both communities. Moreover, this convergence is greater for the wild food plant domain. Comparison of the collected data with ethnobotanical surveys conducted at the end of the 19th Century and the 1980s in one of studied valleys (Germanasca) shows that the majority of the plants recorded in the present study are used in the same or similar ways as they were decades ago. Idiosyncratic plant uses among Waldensians included both archaic uses, such as the fern Botrychium lunaria for skin problems, as well as uses that may be the result of local adaptions of Central and Northern European customs, including Veronica allionii and V. officinalis as recreational teas and Cetraria islandica in infusions to treat coughs. The great resilience of plant knowledge among Waldensians may be the result of the long isolation and history of marginalisation that this group has faced

  6. Natural variability of parasite communities of Macrouridae of the middle and lower slope of the Mediterranean Sea and their relation with fish diet and health indicators

    NASA Astrophysics Data System (ADS)

    Pérez-i-García, D.; Constenla, M.; Soler-Membrives, A.; Cartes, J. E.; Solé, M.; Carrassón, M.

    2017-06-01

    This study examines the parasite communities of Coelorinchus caelorhincus, Coelorinchus mediterraneus, Coryphaenoides guentheri and Coryphaenoides mediterraneus of the middle and lower slopes of the Mediterranean Sea. Histopathological, enzymatic activity (acetylcholinesterase and lactate dehydrogenase), dietary and environmental (oxygen, salinity, temperature and turbidity) information were also obtained. A total of 11 parasite taxa were found in the four fish species, the copepod Hamaticolax resupinus being the only parasite shared by all of them. Coelorinchus mediterraneus, Coryphaenoides guentheri and Cor. mediterraneus exhibited rather homogeneous parasite communities, especially in the case of the latter two. Coelorinchus mediterraneus showed the highest richness of parasite taxa (eight species), whereas C. guentheri and Cor. mediterraneus harboured up to five and six, respectively, and C. caelorhincus up to three. Several of the parasites encountered occurred at very low prevalences (<10%), while only three species were exceptionally prevalent and abundant: Cucullanidae fam. gen. sp. larvae in C. caelorhincus; Lepidapedon desclersae in Coe. mediterraneus and Hysterothylacium aduncum in both Coryphaenoides spp. The abundance of the nematode H. aduncum, present in all host species except for C. caelorhincus, increased with water temperature and depth and became the dominant parasite below 2000 m. Salinity may be an important factor affecting the distribution of H. resupinus. The diet was generally homogeneous between the studied species, C. guentheri being more specialized on suprabenthic/benthic prey. The parasites H. aduncum and Tetraphylidea, and to lesser extent Raphidascaris sp., were associated with the most mobile (swimming) prey consumed by macrourids (Chaetognaths, decapod larvae, and Boreomysis arctica). The parasites L. desclersae, Capillostrongyloides morae and Otodistomum sp. were associated in Coe. mediterraneus with epibenthic prey (ophiuroids

  7. Suprabenthic assemblages from the Capbreton area (SE Bay of Biscay). Faunal recovery after a canyon turbidity disturbance

    NASA Astrophysics Data System (ADS)

    Frutos, Inmaculada; Sorbe, Jean Claude

    2017-12-01

    In the Capbreton area, suprabenthic assemblages were sampled with a sledge towed over the bottom, at different sites located within the upper part of a 'gouf-type' canyon (8 hauls between 642 m and 797 m, on the axis of the thalweg or on flat perched flank terraces such as site K), on the northern adjacent open slope (2 hauls between 500 and 567 m) and on the northern adjacent shelf margin (2 hauls between 151 m and 158 m). A multivariate analysis carried on the faunal data discriminated different assemblages in this area: a near-canyon shelf assemblage (55 species, mainly amphipods and decapods; 3496 ind./100 m2, 40% mysids; dominant species: Nyctiphanes couchii, Leptomysis gracilis, Weswoodilla rectirostris, Anchialina agilis, Scopelocheirus hopei and Philocheras bispinosus); an open slope assemblage (111 species, mainly amphipods and isopods; 249 ind./100 m2, 36% amphipods; dominant species: Disconectes phalangium, Munnopsurus atlanticus and Boreomysis arctica); a canyon E assemblage (129 species, mainly amphipods, mysids and cumaceans; 1172 ind./100 m2, 58% amphipods; dominant species: Melphidippa sp. B, Chelator insignis); a canyon E' assemblage (107 species, mainly amphipods and mysids; 507 ind./100 m2, 73% amphipods; dominant species: Cleonardopsis carinata, Bonnierella abyssorum, Rhachotropis caeca and Arcturopsis giardi); and a temporary canyon assemblage at site K (34 species, mainly amphipods and mysids; 899 ind./100 m2, 85% amphipods; dominant species: Tmetomyx similis, Caeconyx caeculus, Nebalia sp. A and Cleonardopsis carinata). Site K was sampled only four months after a turbidity event, detected on sediment cores (18 cm thick Bouma sequence) taken during the same cruise and triggered by the violent storm ('ouragan Martin', wind up to 200 km/h) which affected the French Atlantic coast on 27 December 1999. The corresponding suprabenthic assemblage showed evidence of deep structural changes after this catastrophic event, characterized by relative low

  8. Diatom succession trends in recent sediments from Lake Baikal and their relation to atmospheric pollution and to climate change

    PubMed Central

    Mackay, A. W.

    1998-01-01

    diatom flora of the lake is currently dominated by several species, such as Aulacoseira baicalensis, A. islandica, Cyclotella minuta and Stephanodiscus binderanus v. baicalensis. All these species, except for C. minuta, have become more common in the lake in approximately the last 130 years, and we hypothesize that these changes may be attributed to a number of different processes linked to an ameliorating climate after the end of the Little Ice Age. The results presented here have important implications for this recently designated World Heritage Site, with regard to future pollution controls and catchment management policies.

  9. Examination of body burden and taint for Iceland scallop (Chlamys islandica) and American plaice (Hippoglossoides platessoides) near the Terra Nova offshore oil development over ten years of drilling on the Grand Banks of Newfoundland, Canada

    NASA Astrophysics Data System (ADS)

    DeBlois, Elisabeth M.; Kiceniuk, Joe W.; Paine, Michael D.; Kilgour, Bruce W.; Tracy, Ellen; Crowley, Roger D.; Williams, Urban P.; Gregory Janes, G.

    2014-12-01

    This paper presents results of analyses of body burdens of metals and hydrocarbons, and taste tests for taint, in Iceland scallop and American plaice performed as part of the Environmental Effects Monitoring (EEM) program for the Terra Nova offshore oil development (Grand Banks of Newfoundland, Canada). Scallop and plaice were collected in a Study Area located within approximately 1 km of drill centres at Terra Nova and in a Reference Area located approximately 20 km from the development. Samples were collected in 1997 to establish a baseline, and from 2000 to 2010, during drilling periods. Scallop adductor muscle tissue was contaminated with >C10-C21 aliphatic hydrocarbons resembling the drilling fluid in the synthetic drilling mud (SBM) used at Terra Nova in 2000, 2002 and 2004, but contamination of adductor muscle was not noted in 2006, 2008 and 2010. The maximum concentration in muscle was 28 mg/kg wet weight, noted in 2002. Scallop viscera was contaminated with hydrocarbons resembling drilling fluid in SBMs near drill centres in all EEM years except 2010. Viscera contamination with >C10-C21 hydrocarbons gradually decreased from a maximum of 150 mg/kg in 2000, to a maximum of 27 mg/kg in 2008; all values were below the laboratory reporting detection limit of 15 mg/kg in 2010. Therefore, evidence from both muscle and viscera indicates a decrease in tissue hydrocarbon contamination in recent years. Barium, another major constituent in drilling muds, has not been noted in scallop adductor muscles at concentrations above the reporting detection limit, but barium was detected in viscera in baseline and EEM years. The maximum concentration of barium in viscera during baseline sampling was 8 mg/kg. The maximum concentration in EEM years (29 mg/kg) was noted in 2000. The maximum concentration in 2010 was 25 mg/kg. The concentration of metals other than barium in scallop tissues was similar between the Terra Nova Study Area and the Reference Area. Hydrocarbons resembling the fluid in SBMs were noted in one American plaice liver sample collected near drill centres in 2000. Otherwise, there has been no evidence of project-related metals or hydrocarbon contamination in plaice liver or fillet samples. There has been no evidence of taint (off-taste) for scallop adductor muscle and plaice fillet tissue in baseline or EEM years. Combined with a parallel study on fish bioindicators at Terra Nova that showed that fish health at Terra Nova was similar to that at the Reference Area (Mathieu et al., 2011), these results indicate little to no detectable biological effects on Iceland scallop and American plaice as a result of Terra Nova activities.

  10. Enrichment and Physiological Characterization of a Cold-Adapted Nitrite-Oxidizing Nitrotoga sp. from an Eelgrass Sediment

    PubMed Central

    Ishii, Kento; Fujitani, Hirotsugu; Soh, Kentaro; Nakagawa, Tatsunori; Takahashi, Reiji

    2017-01-01

    ABSTRACT Nitrite-oxidizing bacteria (NOB) are responsible for the second step of nitrification in natural and engineered ecosystems. The recently discovered genus Nitrotoga belongs to the Betaproteobacteria and potentially has high environmental importance. Although environmental clones affiliated with Nitrotoga are widely distributed, the limited number of cultivated Nitrotoga spp. results in a poor understanding of their ecophysiological features. In this study, we successfully enriched the nonmarine cold-adapted Nitrotoga sp. strain AM1 from coastal sand in an eelgrass zone and investigated its physiological characteristics. Multistep-enrichment approaches led to an increase in the abundance of AM1 to approximately 80% of the total bacterial population. AM1 was the only detectable NOB in the bacterial community. The 16S rRNA gene sequence of AM1 was 99.6% identical to that of “Candidatus Nitrotoga arctica,” which was enriched from permafrost-affected soil. The highest nitrogen oxidation rate of AM1 was observed at 16°C. The half-saturation constant (Km) and the generation time were determined to be 25 μM NO2− and 54 h, respectively. The nitrite oxidation rate of AM1 was stimulated at concentrations of <30 mM NH4Cl but completely inhibited at 50 mM NH4Cl. AM1 can grow well under specific environmental conditions, such as low temperature and in the presence of a relatively high concentration of free ammonia. These results help improve our comprehension of the functional importance of Nitrotoga. IMPORTANCE Nitrite-oxidizing bacteria (NOB) are key players in the second step of nitrification, which is an important process of the nitrogen cycle. Recent studies have suggested that the organisms of the novel NOB genus Nitrotoga were widely distributed and played a functional role in natural and engineered ecosystems. However, only a few Nitrotoga enrichments have been obtained, and little is known about their ecology and physiology. In this study, we

  11. Orbitally-forced Azolla blooms and middle Eocene Arctic hydrology; clues from palynology

    NASA Astrophysics Data System (ADS)

    Barke, Judith; Abels, Hemmo A.; Sangiorgi, Francesca; Greenwood, David R.; Sweet, Arthur R.; Donders, Timme; Lotter, Andre F.; Reichart, Gert-Jan; Brinkhuis, Henk

    2010-05-01

    The presence of high abundances of the freshwater fern Azolla in the early Middle Eocene central Arctic Ocean sediments recovered from the Lomonosov Ridge during IODP Expedition 302, have been related to the presence of a substantial freshwater cap. Azolla massulae, belonging to the newly described Eocene species Azolla arctica Collinson et al., have been found over at least a ~4 m-thick interval. There are strong indications that Azolla has bloomed and reproduced in situ in the Arctic Ocean for several hundreds of thousands of years. Possible causes for the sudden demise of Azolla at ~48.1 Ma include salinity changes due to evolving oceanic connections or sea-level change. Distinct cyclic fluctuation in the Azolla massulae abundances have previously been related to orbitally forced climate changes. In this study, we evaluate the possible underlying forcing mechanisms for these freshwater cycles and for the eventual demise of Azolla in an integrated palynological and cyclostratigraphical approach. Our results show two clear periodicities of ~1.3 and ~0.7 m in all major aquatic and terrestrial palynomorph associations, which we can relate to obliquity (41 ka) and precession (~21 ka), respectively. Cycles in the abundances of Azolla, freshwater-tolerant dinoflagellate cysts, and swamp vegetation pollen show co-variability in the obliquity domain. Their strong correlation suggests periods of enhanced rainfall and runoff during Azolla blooms, possibly associated with increased summer season length and insolation during obliquity maxima. Cycles in the angiosperm pollen record are in anti-phase with the Azolla cycles. We interpret this pattern as edaphically drier conditions on land and reduced associated runoff during Azolla lows, possibly corresponding to obliquity minima. The precession signal is distinctly weaker than that for obliquity, and is mainly detectable in the cold-temperate Larix and bisaccate conifer pollen abundances, which is interpreted as a response to

  12. ER-2 #809 awaits pilot entry for the third flight of the SAGE III Ozone Loss and Validation Experime

    NASA Technical Reports Server (NTRS)

    2000-01-01

    ER-2 #809 awaiting pilot entry for the third flight of the SAGE III Ozone Loss and Validation Experiment (SOLVE). The ER-2, a civilian variant of Lockheed's U-2, and another NASA flying laboratory, Dryden's DC-8, were based north of the Arctic Circle in Kiruna, Sweden during the winter of 2000 to study ozone depletion as part of SOLVE. A large hangar built especially for research, 'Arena Arctica' housed the instrumented aircraft and the scientists. Scientists have observed unusually low levels of ozone over the Arctic during recent winters, raising concerns that ozone depletion there could become more widespread as in the Antarctic ozone hole. The NASA-sponsored international mission took place between November 1999 and March 2000 and was divided into three phases. The DC-8 was involved in all three phases returning to Dryden between each phase. The ER-2 flew sample collection flights between January and March, remaining in Sweden from Jan. 9 through March 16. 'The collaborative campaign will provide an immense new body of information about the Arctic stratosphere,' said program scientist Dr. Michael Kurylo, NASA Headquarters. 'Our understanding of the Earth's ozone will be greatly enhanced by this research.' ER-2s bearing tail numbers 806 and 809 are used as airborne science platforms by NASA's Dryden Flight Research Center. The aircraft are platforms for a variety of high-altitude science missions flown over various parts of the world. They are also used for earth science and atmospheric sensor research and development, satellite calibration and data validation. The ER-2s are capable of carrying a maximum payload of 2,600 pounds of experiments in a nose bay, the main equipment bay behind the cockpit, two wing-mounted superpods and small underbody and trailing edges. Most ER-2 missions last about six hours with ranges of about 2,200 nautical miles. The aircraft typically fly at altitudes above 65,000 feet. On November 19, 1998, an ER-2 set a world record for

  13. "Recent" macrofossil remains from the Lomonosov Ridge, central Arctic Ocean

    NASA Astrophysics Data System (ADS)

    Le Duc, Cynthia; de Vernal, Anne; Archambault, Philippe; Brice, Camille; Roberge, Philippe

    2016-04-01

    The examination of surface sediment samples collected from 17 sites along the Lomonosov Ridge at water depths ranging from 737 to 3339 meters during Polarstern Expedition PS87 in 2014 (Stein, 2015), indicates a rich biogenic content almost exclusively dominated by calcareous remains. Amongst biogenic remains, microfossils (planktic and benthic foraminifers, pteropods, ostracods, etc.) dominate but millimetric to centrimetric macrofossils occurred frequently at the surface of the sediment. The macrofossil remains consist of a large variety of taxa, including gastropods, bivalvia, polychaete tubes, scaphopods, echinoderm plates and spines, and fish otoliths. Among the Bivalvia, the most abundant taxa are Portlandia arctica, Hyalopecten frigidus, Cuspidaria glacilis, Policordia densicostata, Bathyarca spp., and Yoldiella spp. Whereas a few specimens are well preserved and apparently pristine, most mollusk shells displayed extensive alteration features. Moreover, most shells were covered by millimeter scale tubes of the serpulid polychaete Spirorbis sp. suggesting transport from low intertidal or subtidal zone. Both the ecological affinity and known geographic distribution of identified bivalvia as named above support the hypothesis of transportation rather than local development. In addition to mollusk shells, more than a hundred fish otoliths were recovered in surface sediments. The otoliths mostly belong to the Gadidae family. Most of them are well preserved and without serpulid tubes attached to their surface, suggesting a local/regional origin, unlike the shell remains. Although recovered at the surface, the macrofaunal assemblages of the Lomonosov Ridge do not necessarily represent the "modern" environments as they may result from reworking and because their occurrence at the surface of the sediment may also be due to winnowing of finer particles. Although the shells were not dated, we suspect that their actual ages may range from modern to several thousands of

  14. Enrichment and Physiological Characterization of a Cold-Adapted Nitrite-Oxidizing Nitrotoga sp. from an Eelgrass Sediment.

    PubMed

    Ishii, Kento; Fujitani, Hirotsugu; Soh, Kentaro; Nakagawa, Tatsunori; Takahashi, Reiji; Tsuneda, Satoshi

    2017-07-15

    Nitrite-oxidizing bacteria (NOB) are responsible for the second step of nitrification in natural and engineered ecosystems. The recently discovered genus Nitrotoga belongs to the Betaproteobacteria and potentially has high environmental importance. Although environmental clones affiliated with Nitrotoga are widely distributed, the limited number of cultivated Nitrotoga spp. results in a poor understanding of their ecophysiological features. In this study, we successfully enriched the nonmarine cold-adapted Nitrotoga sp. strain AM1 from coastal sand in an eelgrass zone and investigated its physiological characteristics. Multistep-enrichment approaches led to an increase in the abundance of AM1 to approximately 80% of the total bacterial population. AM1 was the only detectable NOB in the bacterial community. The 16S rRNA gene sequence of AM1 was 99.6% identical to that of " Candidatus Nitrotoga arctica," which was enriched from permafrost-affected soil. The highest nitrogen oxidation rate of AM1 was observed at 16°C. The half-saturation constant ( K m ) and the generation time were determined to be 25 μM NO 2 - and 54 h, respectively. The nitrite oxidation rate of AM1 was stimulated at concentrations of <30 mM NH 4 Cl but completely inhibited at 50 mM NH 4 Cl. AM1 can grow well under specific environmental conditions, such as low temperature and in the presence of a relatively high concentration of free ammonia. These results help improve our comprehension of the functional importance of Nitrotoga IMPORTANCE Nitrite-oxidizing bacteria (NOB) are key players in the second step of nitrification, which is an important process of the nitrogen cycle. Recent studies have suggested that the organisms of the novel NOB genus Nitrotoga were widely distributed and played a functional role in natural and engineered ecosystems. However, only a few Nitrotoga enrichments have been obtained, and little is known about their ecology and physiology. In this study, we successfully

  15. Combining cosmogenic radionuclides and amino acid racemization to date late Pliocene glacial deposits exposed on Baffin Island, Nunavut, Canada

    NASA Astrophysics Data System (ADS)

    Refsnider, K. A.; Miller, G. H.

    2009-12-01

    Sequences of glacial deposits spanning the Quaternary are valuable archives recording the effects of glaciation on landscapes through time, but determining the age of such deposits has long challenged geologists. The recent advances in cosmogenic radionuclide (CRN) measurement has made it possible to date some of these deposits, but dating buried glacial sediments in most settings remains problematic. Here we explore a new approach to date the oldest glacial deposits in the Plio-Pleistocene Clyde Foreland Formation of Baffin Island. This formation, approximately 40 m thick, includes interlayered shell-bearing marine, glaciomarine, and glacial sediments deposited along the northern margin of the Laurentide Ice Sheet and earlier continental ice sheets. Previous work on foraminifera assemblages suggests that the deposits span the last ≥2 Ma. By combining CRN measurements (10Be and 26Al) from the glacial units and measurements of the D-alloisoleucine:L-isoleucine ratios (A/I) in valves of the mollusk Hiatella arctica in the marine units overlying a particular glacial deposit, we can calculate the age of the glacial deposit. Because the post-burial temperature history for the mollusks preserved in the Clyde Foreland Formation is poorly constrained, A/I ratios alone cannot be used to determine absolute ages. Instead, we use A/I ratios to identify sediment packages of discrete ages and define a step-wise burial history function for glacial units. A/I ratios of all packages (<0.3 for the total hydrolysate fraction) fall within the A/I interval characterized by linear racemization kinetics, so the age of each package in the burial history function can simply be defined as a fractional age with respect to the total burial age for the glacial deposit of interest. The long duration of burial (26Al/10Be as low as 1.6±0.6 at 2σ) and low initial CRN inventories require that post-burial muogenic production is accounted for using the burial history function. We apply a

  16. Limnological and climatic environments at Upper Klamath Lake, Oregon during the past 45 000 years

    USGS Publications Warehouse

    Bradbury, J.P.; Colman, Steven M.; Dean, W.E.

    2004-01-01

    Upper Klamath Lake, in south-central Oregon, contains long sediment records with well-preserved diatoms and lithological variations that reflect climate-induced limnological changes. These sediment archives complement and extend high resolution terrestrial records along a north-south transect that includes areas influenced by the Aleutian Low and Subtropical High, which control both marine and continental climates in the western United States. The longest and oldest core collected in this study came from the southwest margin of the lake at Caledonia Marsh, and was dated by radiocarbon and tephrochronology to an age of about 45 ka. Paleolimnological interpretations of this core, based upon geochemical and diatom analyses, have been augmented by data from a short core collected from open water environments at nearby Howards Bay and from a 9-m core extending to 15 ka raised from the center of the northwestern part of Upper Klamath Lake. Pre- and full-glacial intervals of the Caledonia Marsh core are characterized and dominated by lithic detrital material. Planktic diatom taxa characteristic of cold-water habitats (Aulacoseira subarctica and A. islandica) alternate with warm-water planktic diatoms (A. ambigua) between 45 and 23 ka, documenting climate changes at millennial scales during oxygen isotope stage (OIS) 3. The full-glacial interval contains mostly cold-water planktic, benthic, and reworked Pliocene lacustrine diatoms (from the surrounding Yonna Formation) that document shallow water conditions in a cold, windy environment. After 15 ka, diatom productivity increased. Organic carbon and biogenic silica became significant sediment components and diatoms that live in the lake today, indicative of warm, eutrophic water, became prominent. Lake levels fell during the mid-Holocene and marsh environments extended over the core site. This interval is characterized by high levels of organic carbon from emergent aquatic vegetation (Scirpus) and by the Mazama ash (7.55 ka

  17. ER-2 #809 on the SAGE III Ozone Loss and Validation Experiment (SOLVE) with pilot Dee Porter prepari

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Lockheed Martin pilot Dee Porter climbs up the ladder wearing a heavy tan pressure suit, preparing to board NASA ER-2 #809 at Kiruna, Sweden, for the third flight in the SAGE III Ozone Loss and Validation Experiment. Assisting him is Jim Sokolik, a Lockheed Martin life support technician. Number 809, one of Dryden's two high-flying ER-2 Airborne Science aircraft, a civilian variant of Lockheed's U-2, and another NASA flying laboratory, Dryden's DC-8, were based north of the Arctic Circle in Kiruna, Sweden during the winter of 2000 to study ozone depletion as part of the SAGE III Ozone Loss and Validation Experiment (SOLVE). A large hangar built especially for research, 'Arena Arctica' housed the instrumented aircraft and the scientists. Scientists have observed unusually low levels of ozone over the Arctic during recent winters, raising concerns that ozone depletion there could become more widespread as in the Antarctic ozone hole. The NASA-sponsored international mission took place between November 1999 and March 2000 and was divided into three phases. The DC-8 was involved in all three phases returning to Dryden between each phase. The ER-2 flew sample collection flights between January and March, remaining in Sweden from Jan. 9 through March 16. 'The collaborative campaign will provide an immense new body of information about the Arctic stratosphere,' said program scientist Dr. Michael Kurylo, NASA Headquarters. 'Our understanding of the Earth's ozone will be greatly enhanced by this research.' ER-2s bearing tail numbers 806 and 809 are used as airborne science platforms by NASA's Dryden Flight Research Center. The aircraft are platforms for a variety of high-altitude science missions flown over various parts of the world. They are also used for earth science and atmospheric sensor research and development, satellite calibration and data validation. The ER-2s are capable of carrying a maximum payload of 2,600 pounds of experiments in a nose bay, the main

  18. Revision of Sternaspis Otto, 1821 (Polychaeta, Sternaspidae)

    PubMed Central

    Sendall, Kelly; Salazar-Vallejo, Sergio I.

    2013-01-01

    Abstract To the memory of William Ronald Sendall Sternaspid polychaetes are common and often abundant in soft bottoms in the world oceans. Some authors suggest that only one species should be recognized, whereas others regard a few species as widely distributed in many seas and variable depths from the low intertidal to about 4400 m. There are some problems with species delineation and the distinctive ventro-caudal shield has been disregarded or barely used for identifying species. In order to clarify these issues, the ventral shield is evaluated in specimens from the same locality and its diagnostic potential is confirmed. On this basis, a revision of Sternaspis Otto, 1821 (Polychaeta: Sternaspidae) is presented based upon type materials, or material collected from type localities. The sternaspid body, introvert hooks and shield show three distinct patterns, two genera have seven abdominal segments and tapered introvert hooks, and one genus has eight abdominal segments and spatulate introvert hooks. The ventro-caudal shield has three different patterns: stiff with ribs, and sometimes concentric lines, stiff with feebly-defined ribs but no concentric lines, and soft with firmly adhered sediment particles. Sternaspis is restricted to include species with seven abdominal segments, falcate introvert hooks, and stiff shields, often exhibiting radial ribs, concentric lines or both. Sternaspis includes, besides the type species, Sternaspis thalassemoides Otto, 1821 from the Mediterranean Sea, Sternaspis affinis Stimpson, 1864 from the Northeastern Pacific, Sternaspis africana Augener, 1918, stat. n. from Western Africa, Sternaspis andamanensis sp. n. from the Andaman Sea, Sternaspis costata von Marenzeller, 1879 from Japan, Sternaspis fossor Stimpson, 1853 from the Northwestern Atlantic, Sternaspis islandica Malmgren, 1867 from Iceland, Sternaspis maior Chamberlin, 1919 from the Gulf of California, Sternaspis princeps Selenka, 1885 from New Zealand, Sternaspis rietschi

  19. Revision of sternaspis otto, 1821 (polychaeta, sternaspidae).

    PubMed

    Sendall, Kelly; Salazar-Vallejo, Sergio I

    2013-01-01

    To the memory of William Ronald Sendall Sternaspid polychaetes are common and often abundant in soft bottoms in the world oceans. Some authors suggest that only one species should be recognized, whereas others regard a few species as widely distributed in many seas and variable depths from the low intertidal to about 4400 m. There are some problems with species delineation and the distinctive ventro-caudal shield has been disregarded or barely used for identifying species. In order to clarify these issues, the ventral shield is evaluated in specimens from the same locality and its diagnostic potential is confirmed. On this basis, a revision of Sternaspis Otto, 1821 (Polychaeta: Sternaspidae) is presented based upon type materials, or material collected from type localities. The sternaspid body, introvert hooks and shield show three distinct patterns, two genera have seven abdominal segments and tapered introvert hooks, and one genus has eight abdominal segments and spatulate introvert hooks. The ventro-caudal shield has three different patterns: stiff with ribs, and sometimes concentric lines, stiff with feebly-defined ribs but no concentric lines, and soft with firmly adhered sediment particles. Sternaspis is restricted to include species with seven abdominal segments, falcate introvert hooks, and stiff shields, often exhibiting radial ribs, concentric lines or both. Sternaspis includes, besides the type species, Sternaspis thalassemoides Otto, 1821 from the Mediterranean Sea, Sternaspis affinis Stimpson, 1864 from the Northeastern Pacific, Sternaspis africana Augener, 1918, stat. n. from Western Africa, Sternaspis andamanensis sp. n. from the Andaman Sea, Sternaspis costata von Marenzeller, 1879 from Japan, Sternaspis fossor Stimpson, 1853 from the Northwestern Atlantic, Sternaspis islandica Malmgren, 1867 from Iceland, Sternaspis maior Chamberlin, 1919 from the Gulf of California, Sternaspis princeps Selenka, 1885 from New Zealand, Sternaspis rietschi Caullery

  20. Evidence for smaller extents of the northwestern Greenland Ice Sheet and North Ice Cap during the Holocene

    NASA Astrophysics Data System (ADS)

    Kelly, M. A.; Osterberg, E. C.; Axford, Y.; Bigl, M.; Birkel, S. D.; Corbett, L. B.; Roy, E. P.; Thompson, J. T.; Whitecloud, S.

    2013-12-01

    The Greenland Ice Sheet (GrIS) and local glaciers on Greenland are responding dynamically to warming temperatures with widespread retreat. GRACE satellite data (e.g., Kahn et al., 2010) and the Petermann Glacier calving events document the recent expansion of ice loss into northwestern Greenland. To improve the ability to estimate future ice loss in a warming climate, we are developing records of the response of the northwestern Greenlandic cryosphere to Holocene climatic conditions, with a focus on past warm periods. Our ongoing research includes analyses of glacial geology, sub-fossil vegetation, lake sediment cores, chironomid assemblages and ice cores combined with glaciological modeling. To constrain past ice extents that were as small as, or smaller than, at present, we recovered sub-fossil vegetation exposed at the receding margins of the GrIS and North Ice Cap (NIC) in the Nunatarssuaq region (~76.7°N, 67.4°W) and of the GrIS near Thule (~76.5°N, 68.7°W). We present vegetation types and radiocarbon ages of 30 plant samples collected in August 2012. In the Nunatarssuaq region, five ages of in situ (rooted) vegetation including Polytrichum moss, Saxifraga nathorstii and grasses located <5 m outboard of the GrIS margin are ~120-200 cal yr BP (range of medians of the 2-sigma calibrated age ranges). Nine ages of in situ Polytrichum, Saxifraga oppositafolia and grasses from ~1-5 m inboard of the NIC margin (excavated from beneath ice) range from ~50 to 310 cal yr BP. The growth of these plants occurred when the GrIS and NIC were at least as small as at present and their ages suggest that ice advances occurred in the last 50-120 yrs. In addition to the in situ samples, we collected plants from well-preserved ground material exposed along shear planes in the GrIS margins. In Nunatarssuaq, two Polytrichum mosses rooted in ground material and exposed along a shear plane in the GrIS margin date to 4680 and 4730 cal yr BP. Near Thule, three ages of Salix arctica

  1. Net-mortality of Common Murres and Atlantic Puffins in Newfoundland, 1951-81

    USGS Publications Warehouse

    Piatt, John F.; Nettleship, David N.; Threlfall, William; Nettleship, David N.; Sanger, Gerald A.; Springer, Paul F.

    1982-01-01

    Band recoveries (N = 315) over 26 years (1951-77) and three surveys of seabird bycatch in inshore fishing nets (1972, 1980-81) indicate that there has been a substantial net-mortality of Atlantic Puffins (Fratercula arctica) and Common Murres (Uria aalge) in Newfoundland coastal waters for the past 2 decades. Offshore (e.g. Grand Banks) gill-netting is limited, but some data suggest that murre net-mortality also occurs offshore at murre wintering areas. The vast majority of inshore net-mortality incidents occur over a 2-week period during the annual inshore spawning migration of capelin (Mallotus villosus), the major prey item for alcids in eastern Canada. Most murres (83%) were drowned in bottom-set (30-185 m) cod (Gadus morhua) gill nets, whereas more puffins were drowned in surface-set salmon (Salmo salar) gill nets or cod traps (55%) than in cod gillnets (45%). Murre band recoveries, colony censuses, and fishing-effort data suggest that at the second largest Common Murre colony in Newfoundland (Witless Bay Seabird Sanctuary, 77,000 breeding pairs) net-mortality was relatively low in the 1950s and early 1960s, but increased during the 1960s as the murre population grew in size and gill-net fishing effort increased in the colony area. By 1971, net-mortality accounted for 70% of murre band recoveries and calculations show that almost 30,000 breeding adults, or about 20% of the local breeding population, were drowned in that year. More reliable estimates of alcid bycatch in the Witless Bay area have been made on the basis of actual bycatch surveys. In 1972 about 20,000 adult murres, or 13% of the breeding stock, were killed in gill-nets. Net-mortality of murres apparently diminished through the 1970s as capelin stocks declined and fewer birds foraged in heavily netted inshore areas. Bycatch surveys in the Witless Bay area in 1980-81 revealed that, relative to previous years, murre net-mortality was greatly reduced and resulted in the loss of only 3-4% of the

  2. Carbon cycling in a high-arctic marine ecosystem - Young Sound, NE Greenland

    NASA Astrophysics Data System (ADS)

    Rysgaard, Søren; Nielsen, Torkel Gissel

    2006-10-01

    which megafauna accounts for 17%. In deeper waters benthic mineralization is 40% lower than in shallow waters and megafauna, primarily brittle stars, accounts for 27% of the benthic mineralization. The carbon that escapes degradation is permanently accumulated in the sediment, and for the locality investigated a rate of 7 g C m -2 yr -1 was determined. A group of walruses (up to 50 adult males) feed in the area in shallow waters (<40 m) during the short, productive, ice-free period, and they have been shown to be able to consume <3% of the standing stock of bivalves ( Hiatella arctica, Mya truncata and Serripes Groenlandicus), or half of the annual bivalve somatic production. Feeding at greater depths is negligible in comparison with their feeding in the bivalve-rich shallow waters.

  3. Sediment deposition and occurrence of selected nutrients, other chemical constituents, and diatoms in bottom sediment, Perry Lake, northeast Kansas, 1969-2001

    USGS Publications Warehouse

    Juracek, Kyle E.

    2003-01-01

    .S. Environmental Protection Agency, concentrations of arsenic, chromium, copper, and nickel in the bottom sediment of Perry Lake typically exceeded the threshold-effects levels, which represent the concentrations above which toxic biological effects occasionally occur. Most nickel concentrations also exceeded the probable-effects level, which represents the concentration above which toxic biological effects usually or frequently occur. Sediment concentrations of metals and trace elements were relatively uniform over time. Statistically significant positive depositional trends for arsenic and manganese and statistically significant negative depositional trends for beryllium, chromium, titanium, and vanadium were indicated. However, the trends may be due solely to analytical variance. Organochlorine compounds either were not detected or were detected at concentrations less than the threshold-effects levels. Evidence of a negative depositional trend for DDE (degradation product of DDT) was consistent with the history of DDT use. Other organochlorine compounds detected were DDD and dieldrin. Diatom occurrence in the bottom sediment of Perry Lake was dominated by species that are indicators of eutrophic (nutrient-rich) conditions. Thus, it was concluded that eutrophic conditions have existed during much of the history of Perry Lake. However, an increase in the relative percentage abundance of the oligotrophic (nutrient-poor) species, combined with the significant positive depositional trends for two oligotrophic species (Aulacoseira islandica and Cyclotella radiosa) and the significant negative depositional trend for one eutrophic species (Stephanodiscus niagarae), indicated that conditions in Perry Lake may have become less eutrophic in recent years. Notable changes in human activity within the basin included a substantial decrease in alfalfa production and a substantial increase in soybean production from 1965 to 2000. These and other changes in human activi

  4. Coastal-change and glaciological map of the Ronne Ice Shelf area, Antarctica, 1974-2002

    USGS Publications Warehouse

    Ferrigno, Jane G.; Foley, K.M.; Swithinbank, C.; Williams, R.S.; Dalide, L.M.

    2005-01-01

    (MSS) images of Ant-arctica and the subsequent repeat coverage made possible with Landsat and other satellite images provided an excellent means of documenting changes in the coastline of Antarctica (Ferrigno and Gould, 1987). The availability of this information provided the impetus for carrying out a comprehensive analysis of the glaciological features of the coastal regions and changes in ice fronts of Antarctica (Swithinbank, 1988; Williams and Ferrigno, 1988). The project was later modified to include Landsat 4 and 5 MSS and Thematic Mapper (TM) (and in some areas Landsat 7 Enhanced Thematic Mapper Plus (ETM+)), RADARSAT images, and other data where available, to compare changes during a 20- to 25- or 30-year time interval (or longer where data were available, as in the Antarctic Peninsula). The results of the analysis are being used to produce a digital database and a series of USGS Geologic Investigations Series Maps (I-2600) consisting of 23 maps at 1:1,000,000 scale and 1 map at 1:5,000,000 scale, in both paper and digital format (Williams and others, 1995; Williams and Ferrigno, 1998; Ferrigno and others, 2002) (available online at http://www.glaciers.er.usgs.gov).