28 resultados para PSEUDO-T-NORMS

em Publishing Network for Geoscientific


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CIPWFULL is a user-friendly, stand-alone FORTRAN software program that is designed to calculate the comprehensive CIPW normative mineral composition of igneous rocks and strictly adheres to the original formulation of the CIPW protocol. This faithful adherence alleviates inaccuracies in normative mineral calculations by programs commonly used by petrologists. Additionally, several of the most important petrological and mineralogical parameters of igneous rocks are calculated by the program. Along with all the regular major oxide elements, all the significant minor elements whose contents can potentially effect the CIPW normative mineral composition are included. CIPWFULL also calculates oxidation ratios for igneous rock samples that have only one oxidation state of iron reported in the specimen analysis. It also provides an option for normalization of analyses to unity on a hydrous-free basis in order to facilitate comparison of norms among rock groups. Other capabilities of the program cater for rare situations, like the presence of cancrinite or exclusion from the norm calculation of rare rocks like carbonatite. Several mineralogical, petrological and discriminatory parameters and indexes are additionally calculated by the CIPWFULL program. The CIPWFULL program is very efficient and flexible and allows for a user-defined free-format input of all the chemical species, and it permits feeding of minor elements as parts per million or oxide percentages. Results of calculations are printed in a formatted ASCII text file and may be optionally casted into a space-delimited text files that are ready to be imported to general spreadsheet programs. CIPWFULL is DOS-based and is implemented on WINDOWS and mainframe platforms.

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How organisms may adapt to rising global temperatures is uncertain, but concepts can emerge from studying adaptive physiological trait variations across existing spatial climate gradients. Many ectotherms, particularly fish, have evolved increasing genetic growth capacities with latitude (i.e. countergradient variation (CnGV) in growth), which are thought to be an adaptation primarily to strong gradients in seasonality. In contrast, evolutionary responses to gradients in mean temperature are often assumed to involve an alternative mode, 'thermal adaptation'. We measured thermal growth reaction norms in Pacific silverside populations (Atherinops affinis) occurring across a weak latitudinal temperature gradient with invariant seasonality along the North American Pacific coast. Instead of thermal adaptation, we found novel evidence for CnGV in growth, suggesting that CnGV is a ubiquitous mode of reaction-norm evolution in ectotherms even in response to weak spatial and, by inference, temporal climate gradients. A novel, large-scale comparison between ecologically equivalent Pacific versus Atlantic silversides (Menidia menidia) revealed how closely growth CnGV patterns reflect their respective climate gradients. While steep growth reaction norms and increasing growth plasticity with latitude in M. menidia mimicked the strong, highly seasonal Atlantic coastal gradient, shallow reaction norms and much smaller, latitude-independent growth plasticity in A. affinis resembled the weak Pacific latitudinal temperature gradient.

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Partial pressure of CO2 (pCO2) and iron availability in seawater show corresponding changes due to biological and anthropogenic activities. The simultaneous change in these factors precludes an understanding of their independent effects on the ecophysiology of phytoplankton. In addition, there is a lack of data regarding the interactive effects of these factors on phytoplankton cellular stoichiometry, which is a key driving factor for the biogeochemical cycling of oceanic nutrients. Here, we investigated the effects of pCO2 and iron availability on the elemental composition (C, N, P, and Si) of the diatom Pseudo-nitzschia pseudodelicatissima (Hasle) Hasle by dilute batch cultures under 4 pCO2 (~200, ~380, ~600, and ~800 µatm) and five dissolved inorganic iron (Fe'; ~5, ~10, ~20, ~50, and ~100 pmol /L) conditions. Our experimental procedure successfully overcame the problems associated with simultaneous changes in pCO2 and Fe' by independently manipulating carbonate chemistry and iron speciation, which allowed us to evaluate the individual effects of pCO2 and iron availability. We found that the C:N ratio decreased significantly only with an increase in Fe', whereas the C:P ratio increased significantly only with an increase in pCO2. Both Si:C and Si:N ratios decreased with increasing pCO2 and Fe'. Our results indicate that changes in pCO2 and iron availability could influence the biogeochemical cycling of nutrients in future oceans with high- CO2 levels, and, similarly, during the time course of phytoplankton blooms. Moreover, pCO2 and iron availability may also have affected oceanic nutrient biogeochemistry in the past, as these conditions have changed markedly over the Earth's history.