Biofiltration of fishpond effluents and accumulation of N-compounds (phycobiliproteins and mycosporine-like amino acids) versus C-compounds (polysaccharides) in Hydropuntia cornea (Rhodophyta)

The biofiltration capacity, biomass-yield and accumulation of N- and C-compounds of Hydropuntia cornea were analyzed. Algae were grown in different conditions for 28 d: outdoor and indoor, with or without fishpond effluents. N-uptake efficiency of these effluents was higher than 95% after 7 d both outdoors and indoors. N-enriched conditions reduced the extent of photoinhibition and increased the maximal quantum yield in H. cornea. The biomass-yield was higher in outdoor grown-algae after 7 d and decreased independently of the treatment after 28 d. N, acid polysaccharide (AP) and mycosporine-like amino acid (MAA)-yields decreased throughout the experiment in all conditions. The highest MAA-yield was observed in fishpond effluent outdoor-grown algae, indicating a positive effect of increased radiation on MAA accumulation. However, APs were higher under N-depleted conditions. The use of MAAs as UV-screening and antioxidants, and the use of AP as immunostimulants are discussed.     

Ground-Motion Hazard Values for Northern Algeria

This study examines distinctive features of ground motion parameters in northern Algeria. An initial computation of seismic hazard in terms of horizontal peak ground acceleration (PGA) and spectral acceleration (SA) at different periods, damped at 5%, is carried out for three different types of soils (rock, stiff soils and soft soils) for return periods of 100 and 475 years. In addition, uniform hazard spectra (UHS) are computed for these two return periods at several locations in the region. Then, the UHS computed for different soil types are proposed as a starting point to define elastic design spectra for building-code purposes. We have used the well-known Newmark-Hall approach. As proposed in the most recent International Building Codes, the SA (0.2 s) value is used to establish the spectral region for lower periods (region controlled by acceleration), whereas the SA (1.0 s) value is used to establish the spectral region for intermediate periods (region controlled by velocity). We also obtained important relations, dependent on site condition, between SA (0.2 s), SA (1.0 s) or SA_max values, and the PGA, for both return periods of 100 and 475 years. Other relationships between PGA or SA_max values have also been derived for return periods of 100 and 475 years, in this case independent of site condition.     

How do early successional patterns in man-made wetlands differ between cold temperate and Mediterranean regions?

The early stages of succession in newly created wetlands should be impacted by the region in which the wetland is located, since climate may have filtered the dominant biological strategies of the taxa leading this process and may condition their dynamics. We studied the early successional patterns of macroinvertebrates within man made ponds, located in cold temperate (Scandinavian Peninsula) and Mediterranean regions (Iberian Peninsula), during the first three years following their creation. We predicted (1) non random subsets of the regional species pool (deterministic assembly) guiding the successional process in cold temperate wetlands, and random (stochastic) assembly in the Mediterranean region; (2) higher successional rates in Mediterranean ponds than in the cold temperate ponds, with contrary episodes of highest and lowest change throughout the year; and (3) a significant difference in the composition of biological traits between regions, due to the dominance of traits adapted to hydrological variability in the Mediterranean region. Hypotheses on community structure (1) and the composition of dominant biological traits (3) were mostly supported – deterministic assembly mechanisms in the cold temperate ponds and stochastic assembly in the Mediterranean ponds; and a dominance of different biological traits between regions, explained by the need to overcome hydrological disturbances in the Mediterranean ponds. The dynamics of succession (2) were explained by climatic factors in the cold temperate region but not in the Mediterranean ponds. We suggest that the intrinsic hydrological variability of Mediterranean lentic systems may be a major factor driving community changes in man-made wetlands in this region. In order to generalize the observed patterns, we performed a meta-analysis of the temporal trends of taxonomic distinctness parameters of other successional studies across a latitudinal gradient in Europe, which supported the differences we had observed between latitudinal extremes.     

Distribution and thickness of sedimentary facies in the coastal dune, beach and nearshore sedimentary system at Maspalomas, Canary Islands

Numerous studies have shown that most beaches and coastal dune systems of the world are currently eroding but very few have investigated the combined sediment budgets of subaerial and nearshore submarine systems. In the case of the dune field of the Maspalomas Natural Special Reserve (in the south of Gran Canaria), the adjacent Maspalomas and El Inglés beaches and the adjacent submarine platform, the sediment budgets have been severely affected by erosion over the past few decades. The objectives of this study were to investigate the availability of sand within the modern sedimentary system, including the coastal dunes, the beaches and the submerged shelf, but also to assess local sediment sinks. An isopach map generated on the basis of topo-bathymetric data and seismic-reflection profiles revealed that sediment thickness varies from 0–22 m in the study area. Expanses of relatively low sediment thickness were identified in the south-western sector of the coastal dune field along Maspalomas beach, and in the nearshore region to the south of this beach. These localized sediment-deficit areas earmark Maspalomas beach as the most vulnerable shore strip threatened by erosion. The shallow seismic data also revealed that the submarine platform south of Maspalomas represents a marine terrace cut into an ancient alluvial fan, thus documenting an influence of the geomorphological heritage on the present-day morphodynamics. A side-scan sonar mosaic of this nearshore platform enabled the delimitation of areas covered by rock, boulders and gravel, vegetated sand patches and a mobile sand facies, the latter including ripple and megaripple fields. The megaripple field in a valley close to the talus of the marine terrace has been identified as a major sediment sink of the Maspalomas sedimentary system. It is fed by south-westerly storm-wave events. The sediment deficit in the coastal dune field and along Maspalomas beach can therefore only be explained by a currently faster loss of sediment to an offshore sink than can be compensated by the supply of sand from outside the system.     

Multi-spectral decomposition of functional autoregressive models

Functional data models provides a suitable framework for the statistical analysis of several environmental phenomena involving continuous time evolution and/or spatial variation. The functional autoregressive model of order p,  p ≥ 1, (FAR(p)) extends to the infinite-dimensional space context the classical autoregressive model AR(p) (see, for example, Mourid T (1993) Processus autorégressiifs d’ordre supérieur. Acad Sci t.317(Sér. I):1167–1172). In this paper, we derive a multidimensional diagonalization of the functional parameters (operators) involved in the FAR(p), p > 1, formulation. The functional state equation is then transformed into a discrete system of scalar state equations. The decomposition obtained is optimal regarding information on spatiotemporal interaction affecting the evolution of the spatial behavior of the process of interest. For functional prediction and filtering, we implement the Kalman filter equations from the diagonal version derived for FAR(p) models. This work has been supported in part by projects MTM2005-08597 of the DGI, MEC, and P05-FQM-00990, P06-FQM-02271 of the Andalousian CICE, Spain.     

Degradation of Monoazo Pigments Red 53:1 and Red 48:2 by Fenton,Photo‐Fenton and UV/Peroxide Reactions

The degradation reactions of two monoazo pigments, namely, Red 53:1 and Red 48:2, by Fenton, photo‐Fenton and UV/H₂O₂ systems have been studied. The efficiencies of the Fenton reactions increased with temperature, but the formation of solid agglomerates was observed when the reactions were carried out above 50°C indicating a coagulant action of Fe⁺² or Fe⁺³. Photo‐Fenton reactions irradiated by sunlight presented the best rate constants for cleavage of the azo bond and the naphthalene rings. The UV/H₂O₂ system exhibited the highest efficiency with respect to the consumption of H₂O₂. The presence of a carbonyl group in the ortho position of the naphthol ring hampered the oxidation of pigment Red 48:2 by hydroxyl radicals. This finding may be explained in terms of the acceptor character of the COOH group, and suggests the formation of a complex containing two six‐membered rings between Fe⁺³ and the pigment molecule.     

Synergic effect of salinity and light-chilling on photosystem II photochemistry of the halophyte,Sarcocornia fruticosa

Laboratory experiments were conduced to assess the synergic effect of chilling and light on photosystem II photochemistry of the halophyte, Sarcocornia fruticosa, grown at different salinity concentrations (0, 170, 340, 510 and 1030 mM). Chlorophyll fluorescence was measured after chilling (at 5 °C in darkness) and light-chilling (at 5 °C and 700 μmol m^?2 s^?1) treatments, and after 24 h of recovery (at 20 °C and 75 μmol m^?2 s^?1). At 5 °C and 700 μmol m^?2 s^?1, plants grown with 0 and 170 mM NaCl showed the lowest F_v/F_m values, whereas quantum efficiency of PSII (Φ_PSII) was higher for plants grown at 170 and 340 mM NaCl, these results being consistent after two exposures to chilling treatments. Susceptibility to photoinhibition decreases when low temperature and high light are combined with high salinity. Therefore, populations of S. fruticosa that occur in arid environments with salinities c. 340 mM could show a higher tolerance to light-chilling.     

Effect of burial on the germination of Opuntia tomentosa's (Cactaceae,Opuntioideae) seeds

Opuntia tomentosa seeds have physiological dormancy and a permeable but hard funicular envelope that restricts water uptake and embryo growth. Dormancy break, germination, and changes in the funiculus were compared in laboratory-stored seeds and in those buried for 7 months at different microsites and later exhumed and stored in the laboratory. The funicular envelopes of both lots were examined with a scanning electron microscope (SEM). Seeds in both lots were: scarified with H₂SO₄ (0, 45, 60 and 90 min), treated with gibberellins (0, 1000 and 2000 ppm) and germinated at the same ages (0, 2, 4, 7, and 10 months after exhumation) at 24 °C. Light effect was determined at 24 °C and 20–35 °C. In laboratory-stored seeds germination was low. Exhumed seeds germinated in ～50%, the remaining ones required scarification and gibberellins, but lost dormancy two months later. Gibberellins reduced germination heterogeneity, and scarification reduced germination; the adverse effect of scarification was offset by gibberellins. Exhumed seeds germinated mainly in darkness at 20–35 °C and partially in far red light at both temperatures. SEM showed that fungi eroded the funiculus reducing its resistance. O. tomentosa could form a seed bank, ensuring its survival under heterogeneous environments.     

Combining 3D Hydraulic Tomography with Tracer Tests for Improved Transport Characterization

Hydraulic tomography (HT) is a method for resolving the spatial distribution of hydraulic parameters to some extent, but many details important for solute transport usually remain unresolved. We present a methodology to improve solute transport predictions by combining data from HT with the breakthrough curve (BTC) of a single forced‐gradient tracer test. We estimated the three dimensional (3D) hydraulic‐conductivity field in an alluvial aquifer by inverting tomographic pumping tests performed at the Hydrogeological Research Site Lauswiesen close to Tübingen, Germany, using a regularized pilot‐point method. We compared the estimated parameter field to available profiles of hydraulic‐conductivity variations from direct‐push injection logging (DPIL), and validated the hydraulic‐conductivity field with hydraulic‐head measurements of tests not used in the inversion. After validation, spatially uniform parameters for dual‐domain transport were estimated by fitting tracer data collected during a forced‐gradient tracer test. The dual‐domain assumption was used to parameterize effects of the unresolved heterogeneity of the aquifer and deemed necessary to fit the shape of the BTC using reasonable parameter values. The estimated hydraulic‐conductivity field and transport parameters were subsequently used to successfully predict a second independent tracer test. Our work provides an efficient and practical approach to predict solute transport in heterogeneous aquifers without performing elaborate field tracer tests with a tomographic layout.