Nutrient balance in the ecosystem of the North Western Adriatic Sea

The effects of biological processes on dissolved inorganic nutrients, dissolved organic nitrogen (DON) and phosphorus (DOP) are considered in the north western Adriatic Sea. The budgets of these nutrients, which represent the sum of production and consumption processes in comparison to advection, are discussed with regard to dissolved inorganic nitrogen ( 15 N labelled) uptake, which basically indicates the biological demand of this fraction of nitrogen by phytoplankton community. The presented data show that, although important, the continental input of dissolved inorganic nitrogen (DIN), mainly nitrate, is utilised and recycled within the coastal marine environment (budget of m 15 r µmol-N·dm m 3 ). In fact, during four cruises (June, 1996; February, 1997; June, 1997; February, 1998), phytoplankton production was mainly driven by regenerated nutrients ( f h 0.4). Regarding dissolved inorganic phosphorus (DIP), the negative budgets observed in most cases (down to m 0.4 r µmol-P·dm m 3 ) confirm, above all, its scarce availability in this basin. Recycling processes rather than continental inputs regulate the availability of this nutrient. In addition, the comparison between DIN and DIP budgets indicates that, in this ecosystem, dissolved inorganic phosphorus is recycled faster than nitrogen through the living particulate and dissolved organic pools. As a consequence of biological activities, a strong production of dissolved organic nitrogen (DON) can occur in summer (up to +22 r µmol-N·dm m 3 ) while DOP shows a more independent behaviour both with respect to its accumulation in the environment and to the observed nitrogen variations.     

Functional zoning for air quality

Environmental local agencies have to enforce European directives that impose a land classification, according to air quality status, to distinguish zones needing further actions from those needing only maintenance. This paper presents a land classification in zones featured by different criticality levels of atmospheric pollution, considering pollutant time series as functional data: we call this proposal “Functional Zoning”. Our proposal is articulated in order to also meet two specific requirements: upscaling pollutant concentration data to the municipality scale, since municipalities are the reference territorial administrative units for undertaking actions; aggregating different pollutants in order to provide a multi-pollutant zoning outcome reflecting the air quality status. Specifically, we present three different alternatives to upscale data from a regular grid to the municipality scale. Then, to aggregate by pollutant, we evaluate two strategies summarizing time series: the assessment of an air quality index and the use of the Multivariate Functional Principal Component Analysis (MFPCA). The partition of municipalities is obtained by clustering air quality time series and MFPCA scores. In particular, the proposed functional zoning is carried out for Piemonte (Northern Italy), considering the hourly concentration fields of the main pollutants. We obtain six classifications of the same land and we propose a comparison study of the different strategies’ results, by mapping and analyzing the differences between clusters’ labels. By taking into account the comparison study’s findings, we finally suggest an analysis strategy to environmental agencies and policy makers to obtain an easily interpretable outcome at a very reasonable computational cost.     

Secondary sexual characters signal fighting ability and determine social rank in Alpine ibex (Capra ibex)

Social dominance is a fundamental aspect of male evolutionary ecology in polygynous mammals because it determines access to estrous females. As it is rarely possible to monitor marked individuals of known morphology, little is known about the determinants of male dominance. We studied the social structure of Alpine ibex males in Gran Paradiso National Park, Italy in 2003, 2006, and 2007. Dominance interactions produced a linear social hierarchy. In ibex males, body mass and horn length are key traits in male-male combat, and both increase with age. We explored the links between age, body mass, horn length, and social rank. Ibex males showed much age-independent phenotypic heterogeneity and rapidly growing males reached high rank at a younger age than slow-growing males. Because there is no trade-off between horn growth and longevity, fast-growing males may face weak potential costs of rapid growth and high fitness benefit of achieving high rank. Violent interactions were more likely to occur between males similar in both mass and horn length, independently of age. We suggest that only high-quality individuals can afford a strategy of rapid growth for both secondary sexual characters, and likely reap substantial fitness benefits.     

Fate of 60Co at a sludge land application site

Vertical distributions of (60)Co are determined in soil cores obtained from a 10-ha grassland, where anaerobically digested sludge was applied by surface spraying from 1986 to 1995 on the U.S. Department of Energy's Oak Ridge Reservation. These results, along with historical application records, are used to estimate vertical-migration rates and perform a mass balance. The presence of (60)Co results solely from the sludge-application process. Soil, vegetation, and surface-water samples were collected. Eleven soil cores were sectioned into 3-cm increments and analyzed by gamma-ray spectrometry. No (60)Co was detected in the vegetation or water samples. The downward migration rate of (60)Co in the upper 15cm of soil ranged from 0.50 to 0.73cm/yr. About 98%, 0.020+/-0.011Bq/cm(2), of (60)Co remained in the upper 15cm of soil, which compared favorably with the expected (60)Co activity based on historical records of 0.019+/-0.010Bq/cm(2).     

Factors promoting or inhibiting Turing instability in spatially extended prey-predator systems

The emergence of inhomogeneities in the distributions of the abundances of spatially extended prey-predator systems is investigated. The method of analysis, based on the notion of diffusive (Turing) instability, is systematically applied to nine different models obtained by introducing an extra-factor into the standard Rosenzweig-MacArthur prey-predator model. The analysis confirms that the standard model is critical in the context of Turing instability, and that the introduction of any small amount of the extra-factor can easily promote or inhibit the emergence of spatial patterns.     

Interaction rules affect species coexistence in intransitive networks

Intransitive communities, those in which species' abilities cannot be ranked in a hierarchy, have been the focus of theoretical and empirical research, as intransitivity could help explain the maintenance of biodiversity. Here we show that models for intransitive competition embedding slightly different interaction rules can produce opposite patterns. In particular, we find that interactions in which an individual can be outcompeted by its neighbors, but cannot outcompete its neighbors, produce negative frequency dependence that, in turn, promotes coexistence. Whenever the interaction rule is modified toward symmetry (the individual and the neighbors can outcompete each other) the negative frequency dependence vanishes, producing different coexistence levels. Macroscopically, we find that asymmetric interactions yield highest biodiversity if species compete globally, while symmetric interactions favor highest biodiversity if competition takes place locally.     

Accumulation of nitrogen and changes in assimilation pigments of lichens transplanted in an agricultural area

The results of a survey aimed at testing the hypothesis that the lichen Evernia prunastri, when transplanted in an agricultural area with high atmospheric NH₃ concentrations, would respond to NH₃ air pollution accumulating nitrogen in its thalli and showing changes in the concentration of assimilation pigments are presented. The results confirmed the hypothesis and showed that all lichen transplants accumulated nitrogen, suggesting that besides the release of atmospheric ammonia by animal stockfarms, the use of N-based fertilizers and the deposition of N-rich dust also may contribute to the high nitrogen availability to lichens in the study area. The result indicated that in the study area both the critical level of NH₃ and the critical load of N for lichens are exceeded and physiological damage is to be expected in sensitive species. The results of assimilation pigments in E. prunastri, with a decrease in the concentration of chlorophylls a and b and carotenoids, as well as chlorophyll degradation to phaeophytin, confirmed this hypothesis. However, owing to the limited data set and pending further studies, these conclusions should be considered as limited to the study area.     

Conservation state of two paintings in the Santa Margherita cliff cave: role of the environment and of the microbial community

Environmental Science and Pollution Research - The conservation of ancient paintings sited in humid environments is an actual challenge for restorers, because it needs the knowledge of the...     

Spatio-temporal dissolved oxygen dynamics in the Orbetello lagoon by fuzzy pattern recognition

This paper models the dissolved oxygen (DO) dynamics in the Orbetello lagoon as a function of the physico-chemical and ecological system variables, including the submerged vegetation, nutrients, and hydrodynamics. It should be viewed as the concluding sequel to a previous paper describing the dynamics of the lagoon ecosystem [Giusti, E., Marsili-Libelli, S., 2006. An integrated model for the Orbetello lagoon ecosystem, Ecol. Model. 196, 379–394] by introducing the missing DO dynamics. The model considers the oxygen demand originating from the decay of carbonaceous and nitrogenous compounds, as well as photosynthesis and natural reaeration by winds and currents as the oxygen producing processes. With a fixed-parameter set the model could accurately reproduce each single circadian DO cycle, but in the long run it failed to extend this fit and could not accommodate the large DO fluctuations induced by the seasonal variability. In order to enhance the model flexibility, a fuzzy pattern recognition algorithm was designed to classify the circadian DO patterns into four typical behaviours, related to the season, and estimate the corresponding parameters, with the overall model output being a fuzzy combination of these sets. The paper discusses several methods to patch the parameter sets and compares their performance in tracking long-term DO variations. A final assessment of the model validity is obtained by incorporating the whole DO dynamics (model, fuzzy pattern recognition and parameter combination) into the general lagoon model and producing a consistently correct series of DO daily distributions over a yearly cycle. Thus the paper contains both a practical and a methodological aspect. The practical one is the linking of all the lagoon dynamics to the dissolved oxygen kinetics in order to clarify to what extent macroalgae and macrophytes influence the oxygen balance. The methodological aspect consists of extending the validity of short-term models to long time-horizons through a patching technique supported by fuzzy pattern recognition.