Anaerobic biodegradability of leachate from MSW intermediate landfill

Anaerobic digestion has been used for decades to treat leachate from municipal solid waste landfills.Due to the characteristics of this kind of effluent, the biodegradability results have not been as satisfactory as could be hoped. Consequently, this area has long been a focus of study. This paper contributes to knowledge of the characteristics of biodegradability of this kind of waste effluent, through application to a real case. Biodegradation performance was studied in depth using a range of physicochemical parameters and the amount of methane produced by various volumetric ratios of substrate: inoculum between 2:50 and 50:50 at 35 ºC and atmospheric pressure by using anaerobic batch tests in 500 mL bottles. It has been observed an optimal situation for the ratios between 16:50 and 24:50 ratios with values of biodegradability COT 45% and 35% in COD. For smaller proportions it has detected the completion of the lack of readily biodegradable substrate. For higher proportions it is considered that the ammoniacal nitrogen has had an inhibiting effect on the anaerobic  process

Historic exposure to herbivores, not constitutive traits, explains plant tolerance to herbivory in the case of two Medicago species (Fabaceae)

Altres ajuts: Direcció General de Política Universitària i Recerca (Govern de les Illes Balears) FPI/1925/2016Mechanisms that allow plants to survive and reproduce after herbivory are considered to play a key role in plant evolution. In this study, we evaluated how tolerance varies in species with different historic exposure to herbivores considering ontogeny. We exposed the range-restricted species Medicago citrina and its closely related and widespread species M. arborea to one and two herbivory simulations (80 % aerial biomass loss). Physiological and growth parameters related to tolerance capacity were assessed to evaluate constitutive values (without herbivory) and induced tolerance after damage. Constitutive traits were not always related to greater tolerance, and each species compensated for herbivory through different traits. Herbivory damage only led to mortality in M. citrina; adults exhibited root biomass loss and increased oxidative stress after damage, but also compensated aerial biomass. Despite seedlings showed a lower death percentage than adults after herbivory in M. citrina, they showed less capacity to recover control values than adults. Moderate tolerance to M. arborea herbivory and low tolerance to M. citrina is found. Thus, although the constitutive characteristics are maintained in the lineage, the tolerance of plants decreases in M. citrina. That represents how plants respond to the lack of pressure from herbivores in their habitat

Preliminary results on climate change evidence from coprolites of Myotragus balearicus Bate 1909 (Artiodactyla, Caprinae)

Plants may vary their stomata density as a function of environmental factors, such as [CO2], drought and temperature. Under the present atmospheric conditions, it is expected that leaves have different stomata density than they had hundreds or thousands of years ago, due to the rise of CO2 in the atmosphere. Microhistological analyses of coprolites of the extinct Myotragus balearicus from Cova Estreta (Pollença, Mallorca), with a radiocarbon age of 4950 ± 38 BP (3775-3640 2σ cal BC; Wk-33010), have shown a diet including an important amount of Buxus balearica epidermal fragments. Three of these coprolites were used to estimate the stomata density on Buxus balearica epidermal fragments from this period. Additionally, three samples of the endangered Buxus balearica, the sole species of Buxus currently present on Mallorca, were collected in three different localities and leaves were examined under microscopy to determine the stomata density. A significant difference between epidermal fragments from coprolites and epidermal fragments of living plants (c² = 34.46, P<0.0001, L-R c² test), with a density average of 27.21 and 19.05 stomata/mm2 res pectively, has been recorded. The current lower density of stomata could be a plant response to climatic change in the Mediterranean islands

Age estimation obtained from analysis of octopus (Octopus vulgaris Cuvier, 1797) beaks: Improvements and comparisons

Two methods are currently available for age estimation in octopus beaks. They have been applied to the same specimen from a sample of 30 individuals of Octopus vulgaris caught in central-eastern Atlantic waters. These techniques aim at revealing growth increments in the rostrum sagittal sections (RSS) and lateral wall surfaces (LWS) of octopus upper and lower beaks. Both methods were improved to reduce the time of sample preparation and to enhance the appearance of the increments. For each individual, two independent readings were done for upper and lower beak sections, as well as for the lateral wall surfaces. Vertical reflected light (epifluorescence) and image analysis system were shown to be useful in the observation and analysis of the sequence of increments. Precision of the ageing, increment counts obtained by both techniques, and increment widths were discussed. Using upper beak RSS led to more precise age estimates, whereas preparing LWS was quicker and simpler, and revealed a higher number of increments. Therefore, our study recommends counting growth increments in LWS of beaks to age adult common octopus

How old are giant squids? First approach to aging Architeuthis beaks

The giant squid Architeuthis dux Steenstrup, 1857 is one of the largest and most enigmatic marine species. Its age estimation remains controversial with many estimates of maximum age ranging from 1 to 14 yrs. Successful results regarding the study of aging in cephalopod beaks for some octopod and oegopsid squids support using these structures for age estimation. We analyzed the beaks of 10 individuals, caught between 1995 and 2006, with reconstructed dorsal mantle lengths (DMLs) between 823 and 1418 mm. The beaks were measured and weighed, and their microstructure was analyzed in three ways: (1) in the rostrum area [rostrum sagittal sections (RSS)] for both upper and lower jaws, and the (2) inner lateral wall surfaces (LWS) and (3) inner crest surfaces (CS) for upper jaws. A constant sequence of increments was observed along the RSS, indicating that the use of lower jaws is more feasible due to the higher erosion and tighter packing of increments of upper jaws. The statolith of one individual was analyzed, resulting in 520 increments (579 increments from RSS of its lower jaw). Assuming daily deposition, the age estimations in RSS between 411 and 674 d suggest rapid growth of A. dux, averaging 1.97 mm DML d–1 (SD 0.45). When maximum ages were estimated by applying these results to the largest measured specimens in the literature (e.g., 2400 mm DML), an age of approximately 3 yrs was obtained. Analysis over a greater size range of individuals would allow more accurate age estimations of this emblematic squid.En prensa1,14

Age of spent Octopus vulgaris and stress mark analysis using beaks of wild individuals

Age estimation of the cephalopod Octopus vulgaris by using beaks has improved in recent years, but maximum age and longevity in the wild have not been confirmed due to the low availability of senescent wild octopuses. In this study, a beak analysis of lateral wall surfaces (LWS) from 20 spent specimens confirmed the one-year lifecycle of the species in Central East Atlantic waters. Stress marks (checks) were clearly located in the daily increment sequence of rostrum sagittal sections (RSS). The highest daily variations in sea surface temperature (ΔT) that occurred during the last months of their lifetimes coincided with the locations of the marks on the beak, enabling confirmation of O. vulgaris beaks as life recorders for the first time. It also supports the daily deposition of RSS beak increments in the wild. Individuals were grouped into two main zones, at 20ºN and 18ºN respectively. Both groups showed different thermal check patterns, in accordance with the oceanographic differences. Two other checks (not coinciding with high values of ΔT) were observed in RSS at averages of 15 and 28 days before death, respectively, which were interpreted as responding to senescent-related events.Instituto Espanol de Oceanografi