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We investigated the mode of growth of flat-topped mud volcanoes, through the study of three active edifices onshore Azerbaijan: they are the Bozdag-Guzdek, the Ayazakhtarma and the Akhtarma-Pashaly mud volcanoes. The three edifices are up to 80 m high and 3 km wide, and the recurrence time between eruptions from a few months to a few years. Surface changes during and between eruptions were documented by a combination of mapping from satellite pictures, repeated direct observation over five years and structural analysis. In addition, resistivity profiles and microgravity measurements were used to decipher their subsurface geometries. We interpret the flat-topped character of the mud volcanoes as the result of rapid “isostatic” readjustment of a brittle surface crust, < 1 m to tens of meters thick, overlying a ductile layer. The surface structure typically shows a concentric transition from an extensional regime in the vicinity of the emission center, to strike slip movements in a median ring, to a compressional regime with thrusts, and pop-up blocks or folds in the outer part of the plateau. Both the flat surface of these mud volcanoes and observed radial displacements of the surface, combined with the very low Bouguer anomaly of the Ayazakhtarma mud volcano, give arguments to propose that km-diameter, flat-topped mud volcanoes likely reflect the presence at a shallow depth (a few tens of meters?) of a large volume of soft mud. Rapid compaction at the surface forms a crust that moves away from a central feeding area, thereby transferring mud added at the center into lateral spreading, building a Coulomb prism all around the mud volcano and strongly limiting vertical buildup.

Measurements of (<i>p, &rho;, T</i>) properties of standard seawater with practical salinity <i>S</i>≈35, temperature <i>T</i>=(273.14 to 468.06) K and pressures, <i>p</i>, up to 140 MPa are reported with the reproducibility of the density measurements observed to be in the average percent deviation range Δ&rho;/&rho;=&plusmn;(0.01 to 0.03)%. The measurements are made with a newly constructed vibration-tube densimeter which is calibrated using double-distilled water, methanol and aqueous NaCl solutions. Based on these and previous measurements, an empirical expression for the density of standard seawater has been developed as a function of pressure and temperature. This equation is used to calculate other volumetric properties including isothermal compressibility, isobaric thermal expansibility, differences in isobaric and isochoric heat capacities, the thermal pressure coefficient, internal pressure and the secant bulk modulus. The results can be used to extend the present equation of state of seawater to higher temperatures for pressure up to 140 MPa.

Phragmites australis is a cosmopolitan grass and often the dominant species in the ecosystems it inhabits. Due to high intraspecific diversity and phenotypic plasticity, P. australis has an extensive ecological amplitude and a great capacity to acclimate to adverse environmental conditions; it can therefore offer valuable insights into plant responses to global change. Here we review the ecology and ecophysiology of prominent P. australis lineages and their responses to multiple forms of global change. Key findings of our review are that: (1) P. australis lineages are well-adapted to regions of their phylogeographic origin and therefore respond differently to changes in climatic conditions such as temperature or atmospheric CO2; (2) each lineage consists of populations that may occur in geographically different habitats and contain multiple genotypes; (3) the phenotypic plasticity of functional and fitness-related traits of a genotype determine the responses to global change factors; (4) genotypes with high plasticity to environmental drivers may acclimate or even vastly expand their ranges, genotypes of medium plasticity must acclimate or experience range-shifts, and those with low plasticity may face local extinction; (5) responses to ancillary types of global change, like shifting levels of soil salinity, flooding, and drought, are not consistent within lineages and depend on adaptation of individual genotypes. These patterns suggest that the diverse lineages of P. australis will undergo intense selective pressure in the face of global change such that the distributions and interactions of co-occurring lineages, as well as those of genotypes within-lineages, are very likely to be altered. We propose that the strong latitudinal clines within and between P. australis lineages can be a useful tool for predicting plant responses to climate change in general and present a conceptual framework for using P. australis lineages to predict plant responses to global change and its consequences.