Riverine dominance of a nearshore marine demersal food web: evidence from stable isotope and C/N ratio analysis     

AM de Lecea  AJ Smit  ST Fennessy 《African Journal of Marine Science》2016,38(1):S181-S192

The Thukela Bank, KwaZulu-Natal, supports a diverse ecosystem and South Africa’s only prawn fishery. Oceanographic studies suggest riverine input is not important for the biology of this system, whereas biological studies suggest the contrary, with prawn catches increasing with increased fluvial run-off. The aim of this study was to determine (i) the importance of riverine and marine organic matter for the Thukela Bank food web; and (ii) whether there are seasonal changes in the Thukela River stable isotope values, and, if so, whether these are reflected in the isotope values of demersal organisms. Estuarine organic matter, sediments and demersal organisms were collected from several sites across the bank in the wet and dry seasons of 2008, 2009 and 2010. Marine particulate organic matter was also collected in 2010 and analysed for δ13C and δ15N, as well as C/N ratios. There were strong seasonal changes in isotopic values of organic matter and fauna, especially faunal δ13C. There was an apparent time-lag in organisms assimilating riverine organic matter isotopic values, with the isotopic signature of demersal organisms reflecting that of riverine organic matter from the previous season, which is likely the result of tissue turnover time. In 2010, Thukela Bank sediment organic matter was of riverine origin and this maintained the demersal food web. We conclude that Thukela River organic matter is an important input to the food web of the Thukela Bank, indicating that any future damming of the catchment area could have serious consequences for this ecosystem.  相似文献   

Global fossil energy markets and climate change mitigation – an analysis with REMIND     

Nico?BauerEmail author  Ioanna?Mouratiadou  Gunnar?Luderer  Lavinia?Baumstark  Robert?J.?Brecha  Ottmar?Edenhofer  Elmar?Kriegler 《Climatic change》2016,135(1):69-83

We analyze the dynamics of global fossil resource markets under different assumptions for the supply of fossil fuel resources, development pathways for energy demand, and climate policy settings. Resource markets, in particular the oil market, are characterized by a large discrepancy between costs of resource extraction and commodity prices on international markets. We explain this observation in terms of (a) the intertemporal scarcity rent, (b) regional price differentials arising from trade and transport costs, (c) heterogeneity and inertia in the extraction sector. These effects are captured by the REMIND model. We use the model to explore economic effects of changes in coal, oil and gas markets induced by climate-change mitigation policies. A large share of fossil fuel reserves and resources will be used in the absence of climate policy leading to atmospheric GHG concentrations well beyond a level of 550 ppm CO₂-eq. This result holds independently of different assumptions about energy demand and fossil fuel availability. Achieving ambitious climate targets will drastically reduce fossil fuel consumption, in particular the consumption of coal. Conventional oil and gas as well as non-conventional oil reserves are still exhausted. We find the net present value of fossil fuel rent until 2100 at 30tril.US$ with a large share of oil and a small share of coal. This is reduced by 9 and 12tril.US$ to achieve climate stabilization at 550 and 450 ppm CO₂-eq, respectively. This loss is, however, overcompensated by revenues from carbon pricing that are 21 and 32tril.US$, respectively. The overcompensation also holds under variations of energy demand and fossil fuel supply.  相似文献   

Response to commentary by J. L. Bamber,W. P. Aspinall and R. M. Cooke (2016)     

Hylke de Vries  Roderik S. W. van de Wal 《Climatic change》2016,137(3-4):329-332

In a commentary paper, Bamber et al. (Nat Clim Change 3:424–427, 2016) respond to our recent assessment (De Vries and Van de Wal Clim Change 1–14, 2015) of their expert judgment based study on projections of future sea level rise due to the melting of the large ice sheets (Bamber and Aspinall Nat Clim Chang 3:424–427, 2013). In this response we comment on their remarks.  相似文献   

Application of climatic indices to analyse viticultural suitability in Extremadura,south-western Spain     

Francisco J. Moral  Francisco J. Rebollo  Luis L. Paniagua  Abelardo García  Enrique Martínez de Salazar 《Theoretical and Applied Climatology》2016,123(1-2):277-289

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Fuel moisture sensitivity to temperature and precipitation: climate change implications   总被引：1，自引：0，他引：1  

M. D. Flannigan  B. M. Wotton  G. A. Marshall  W. J. de Groot  J. Johnston  N. Jurko  A. S. Cantin 《Climatic change》2016,134(1-2):59-71

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On the Space-Time Structure of Sheared Turbulence     

Martin de Maré  Jakob Mann 《Boundary-Layer Meteorology》2016,158(3):453-471

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Comparison of Estimated Atmospheric Boundary Layer Mixing Height in the Arctic and Southern Great Plains under Statically Stable Conditions: Experimental and Numerical Aspects   总被引：1，自引：0，他引：1  

A.A. Aliabadi  R.M. Staebler  J. de Grandpré  A. Zadra  P.A. Vaillancourt 《大气与海洋》2016,54(1):60-74

The atmospheric boundary layer mixing height (MH) is an important bulk parameter in air quality (AQ) modelling. Formulating this parameter under statically stable conditions, such as in the Arctic, has historically been difficult. In an effort to improve AQ modelling capacity in North America, MH is studied in two geographically distinct areas: the Arctic (Barrow, Alaska) and the southern Great Plains (Lamont, Oklahoma). Observational data from the Atmospheric Radiation Measurement program, Climate Research Facility and numerical weather forecasting data from Environment Canada's Regional Global Environmental Multiscale (GEM15) model have been used in order to examine the suitability of available parameterizations for MH under statically stable conditions and also to compare the level of agreement between observed and modelled MH. The analysis period is 1 October 2011 to 1 October 2012. The observations alone suggest that profile methods are preferred over surface methods in defining MH under statically stable conditions. Surface methods exhibit poorer comparison statistics with observations than profile methods. In addition, the fitted constants for surface methods are site-dependent, precluding their applicability for modelling under general conditions. The comparison of observations and GEM15 MH suggests that although the agreement is acceptable in Lamont, the default model surface method contributes to a consistent overprediction of MH in Barrow in all seasons. An alternative profile method for MH is suggested based on the bulk Richardson number. This method is shown to reduce the model bias in Barrow by a factor of two without affecting model performance in Lamont.  相似文献   

Seasonal influence of the sea surface temperature on the low atmospheric circulation and precipitation in the eastern equatorial Atlantic     

Rémi Meynadier  Gaëlle de Coëtlogon  Marion Leduc-Leballeur  Laurence Eymard  Serge Janicot 《Climate Dynamics》2016,47(3-4):1127-1142

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goGPS: open-source MATLAB software     

Herrera  Antonio M.  Suhandri  Hendy F.  Realini  Eugenio  Reguzzoni  Mirko  de Lacy  M. Clara 《GPS Solutions》2016,20(3):595-603

GPS Solutions - goGPS is a positioning software application designed to process single-frequency code and phase observations for absolute or relative positioning. Published under a free and...  相似文献   

Ionospheric tomography using GNSS: multiplicative algebraic reconstruction technique applied to the area of Brazil     

Fabricio dos Santos Prol  Paulo de Oliveira Camargo 《GPS Solutions》2016,20(4):807-814

Experimental analysis was performed using multiplicative algebraic reconstruction technique (MART) to map the ionosphere over Brazil. Code and phase observations from the global navigation satellite system (GNSS) together with the international reference ionosphere (IRI) enabled the estimation of ionospheric profiles and total electron content (TEC) over the entire region. Twenty-four days of data collected from existing ground-based GNSS receivers during the recent solar maximum period were used to analyze the performance of the MART algorithm. The results were compared with four ionosondes. It was demonstrated that MART estimated the electron density peak with the same degree of accuracy as the IRI model in regions with appropriate geometrical coverage by GNSS receivers for tomographic reconstruction. In addition, the slant TEC, as estimated with MART, presented lower root-mean-square error than the TEC calculated by ionospheric maps available from the International GNSS Service (IGS). Furthermore, the daily variations of the ionosphere were better represented with the algebraic techniques, compared to the IRI model and IGS maps, enabling a correlation of the elevation of the ionosphere at higher altitudes with the equatorial ionization anomaly intensification. The tomographic representations also enabled the detection of high vertical gradients at the same instants in which ionospheric irregularities were evident.  相似文献