Microbial-meiofaunal interrelationships in some tropical intertidal sediments

Interrelationships among microbial and meiofaunal communities were examined for one year at four intertidal mangrove and sandflat habitats in tropical northeastern Australia. None of the microbial and meiofaunal communities correlated with physical factors over the year as densities of most microbial and meiofaunal groups, bacterial productivity and specific growth rates (μ) of bacteria fluctuated significantly over time at each habitat with no distinct seasonality. However, over a tidal cycle, bacterial growth rates were significantly affected by tidal flooding and exposure on the sandflat; bacterial growth rates increased with increasing sediment temperatures upon exposure during daylight. Protozoan and meiofaunal abundances generally did not change significantly over tidal cycles. There were few significant correlations and no time lags of bacterial growth rates, and bacterial and microalgal (as chlorophyll a) densities with protozoans and meiobenthos (including nematode species and trophic groups) over the year or during tidal cycles. In concert with the very high rates of bacterial productivity (–x = 475 mgC ˙ m–2 d–1; range; 45-1725 mgC ˙ m–2 d–1) measured in these tropical sediments, the results suggest that protozoan and meiofaunal communities may not be tightly coupled to the dynamics of bacterial and microalgal communities in some tropical intertidal habitats

Re-thinking functional food development through a holistic approach

Although the interest towards functional food has dramatically increased, several factors jeopardize their effective development. A univocally recognized definition and a dedicated regulation for this emerging food category is lacking, and a gap exists between the technological and the nutritional viewpoints. Involved actors speak different languages, thus impinging the progression towards an integrated approach for functional food development. A holistic approach to rationalize functional food development was here proposed, i.e., the \u201cFunctional Food Development Cycle\u201d. First regulation and definitions were reviewed. The technological approaches for functional food design were then described, followed by the efficacy evaluation ones. Merging the technological and the evaluation viewpoints, by identifying the best compromise between quality and functionality, is pivotal to develop effective functional foods. Finally, delivering functional food on the market requires dedicated communication strategies. These in turn can provide information about consumer needs, thus representing an input for regulatory bodies to drive the development of functional food, feeding it within an iterative and virtuous holistic cycle

Effect of physical disturbance on population dynamics and trophic interactions among microbes and meiofauna

A series of laboratory experiments was conducted to assess the effects of physical disturbance of surface sediments on trophic interactions among bacteria, protozoa and meiofauna. Bacteria, zooflagellates, and populations of the hypotrich ciliate Aspidisca sp. and the nematode Diplolaimella chitwoodi were, at most sampling periods, not significantly affected by small-scale, daily disturbances. However, populations of the epibenthic harpacticoid copepod Tisbe holothuriae became disproportionately abundant in disturbed cultures.Bacterial numbers, growth rates and doubling times were affected little by the presence of meiofauna. The response of zooflagellates was not clear; populations of the ciliate Aspidisca sp. were, at most sampling intervals, significantly more abundant in the presence of either meiofauna species.Small-scale disturbances of surface sediments, perhaps regardless of cause, do not appear to be important mechanisms in the structuring and functioning of infaunal meiobenthos-microbial food webs. The dynamics of microbe-meiofauna interactions in sediments are ultimately regulated by the amounts of essential nutrients derived from detritus. Disturbances may be more important for some epifaunal meiobenthos dependent upon migration to disturbed habitats for their survival

The dynamics of benthic nutrient pools and fluxes in tropical mangrove forests

Variations in benthic nutrient pools and rates of dissolved nutrient exchange between the forest floor and tidal waters were examined over a 5-yr period in mixed Rhizophora forests lining Coral Creek on Hinchinbrook Island in Queensland, Australia. Seasonal and spatial changes in redox status, porewater and solid-phase nutrients, and in exchange rates were not consistent and did not correlate with temperature. Below-ground roots, on average, accounted for ≈79%, 37% and 26% of bulk sediment TOC, total N and total P pools, respectively. Porewater nutrient concentrations were dominated by Si(OH)4+ and DON with consistently low levels of NO2− + NO3−. At most sampling periods, porewater NH4+ and PO43− concentrations were higher in creek bank sediments than in mangrove sediments indicating uptake by trees. These sediments have low adsorption capacity (K = 0.17–0.47) for NH4+, but a moderate capacity (K = 0.8–4.8) for PO43− adsorption. Most measured benthic fluxes of dissolved nitrogen and phosphorus showed uptake by sediments, prop roots and timber lying on the forest floor. Relative (per ha) estimates indicate that low-intertidal Rhizophora forests import ≈2220 mmol N ha−1d−1 and ≈496 mmol P ha−1d−1, with sediments accounting for nearly all uptake while Si is exported (≈2475 mmol ha−1d−1. Mid-intertidal forests import ≈1385, 93 and 4720 mmol ha−1d−1 of N, P and Si, respectively; sediments, prop roots and timber respectively account for 36%, 62% and 2% of the N import. Mid-intertidal sediments account for all net P uptake, but prop roots and sediments account for 60% and 40% of total Si uptake. On an absolute basis, low-intertidal forests (78 ha total area) in Coral Creek import ≈881 kgN yr−1, 436 kgP yr−1 and export 1963 kgSi yr−1, and the mid-intertidal forests (338 ha total area) import ≈2392 kgN yr−1, 356 kgP yr−1 and 16300 kgSi yr−1. The sum of these estimates equates to ≈95% of the net annual import of total dissolved N and ≈66% of the net annual import of total dissolved P into the Coral Creek tidal basin from adjacent coastal waters. By difference, ≈14337 kgSi yr−1 is imported into the system. This indicates that mangrove forests are a very efficient sink of dissolved nitrogen, phosphorus and silicon in this tidally-driven coastal ecosystem. This import may be driven by the consistently high rates of microbial and plant growth and productivity within the forests

Effect of different oleogelators on lipolysis and curcuminoid bioaccessibility upon in vitro digestion of sunflower oil oleogels

Sunflower oil enriched with curcuminoid compounds (CUs) was gelled by adding 5% (w/w) saturated monoglycerides (MG), rice bran waxes (RW) or a mixture of \u3b2-sitosterol and \u3b3-oryzanol (PS). The resulting oleogels differed for rheological properties and firmness due to the difference in gel network structure. PS oleogel was the firmest sample followed by RW and MG ones. Upon in vitro digestion, fatty acid release as a function of digestion time was greatly affected by oleogel structure: the extent of lipolysis decreased as oleogel strength increased (PS < RW < MG). On the other hand, the nature of the oleogelator affected CUs bioaccessibility, which was lower in oleogels containing crystalline particles (MG and RW). These findings appear interesting in the attempt to develop oleogels able to control lipid digestion as well as to deliver bioactive molecules in food systems

Modulation of Extra Virgin Olive Oil Digestibility through Oleogelation

Background. Extra virgin olive oil (EVOO) represents a key player in the Mediterranean diet for its health-promoting capacity. Although its use as a functional ingredient would be particularly interesting, the direct addition of EVOO to food is challenging due to its liquid state. EVOO conversion into a solid-like material through by oleogelation could enlarge its possible applications. Methods. EVOO was gelled by adding 10% (w/w) of saturated monoglycerides (MG), rice bran waxes (RW), sunflower waxes (SW) or a β-sitosterol/γ-oryzanol mixture (PS). Oleogels were characterised for their structure and subjected to static in vitro digestion. The fatty acid release and destructuring behavior were assessed. Results. The resulting oleogels differed for rheological properties and firmness due to the differences in gel network structure. PS oleogel was the firmest sample followed by SW, RW and MG ones. During in vitro digestion, the fatty acid release was significantly lower for all oleogels compared to unstructured oil. The different network provided by the four oleogelators not only influenced FA release, but also the intestinal micellar size. Conclusion. Acquired results could open new horizons for EVOO application through oleogelation to obtain novel EVOO-based fat replacers and better deliver the EVOO health functionalities

Climate adaptive urban measures in Mediterranean areas: Thermal effectiveness of an advanced multilayer green roof installed in Palermo (Italy)

Several nature based and climate adaptive solutions have been proposed to improve cities resilience to the effects of global warming and restore natural processes in strongly anthropized areas. Green roofs are among the most efficient nature based solutions to address recurrent urban challenges, such as pluvial floods and urban heat islands. Various benefits offered by green roofs are rather known, such as their capacity to enhance buildings thermal insulation; green roofs also favor urban biodiversity, improving buildings aesthetic value and human well being. Multilayer green roofs (MGRs) are green roofs with an additional layer that increases their water storage capacity. Deep analyses on MGRs are still lacking due to their recent development, and the few works in literature are prevalently focused on their stormwater retention primary function. This work explores the thermal function of an experimental MGR prototype installed in Palermo (Italy), comparing its response to local climate with that of an unaltered portion of the rooftop through the analysis of surface temperature time series collected over a two years monitoring period. Performances are evaluated thought various daily thermal indices, also analyzing the role of the water stored into the system. Results contribute to raise awareness about the benefits arising from the use of MGRs in semi-arid Mediterranean urban areas, confirming, as main thermal advantage, their cooling effect, with mean daily surface temperature reduced by 8.4% outdoor and 5.8% indoor; performances increases with water storage and are particularly evident during the hot and dry summers that typically characterize such regions

Real-World Engagement with Controversial Issues in History and Social Studies: Teaching for Transformative Experiences and Conceptual Change

Controversial issues have been established within the larger framework of civic education as an effective pedagogical approach to developing critical thinking in the classroom, preparing students with intellectual habits necessary for participation in scholarship, civic life and democracy. In this study, we found that a pedagogical intervention, Teaching for Transformative Experience in History, in some cases led to significantly higher engagement with political concepts beyond the classroom, and in other cases, the intervention led to significantly improved conceptual change. The study addresses some of the challenges presented by the research on civic education, providing a potential framework for developing pedagogical practice in history and social studies education that grounds a participatory, meaning-making process in curriculum design and assessment framed by controversial issues

Nonlinear models of the bump cepheid HV 905 and the distance modulus to the large magellanic cloud

Nonlinear pulsation models have been used to simulate the light curve of the LMC bump Cepheid HV 905. In order to reproduce the light curve accurately, tight constraints on the input parameters M, L, and T-eff are required. The results, combined with accurate existing V and I photometry, yield an LMC distance modulus of 18.51 +/- 0.05, and they show that the luminosity of HV 905 is much higher than expected from the mass-luminosity relation of stellar evolution theory. If we assume that the pulsation models are accurate, this suggests that there is a larger amount of convective core overshoot during the main-sequence evolution of stars with M similar to 5 M. than is usually assumed