Flow Of Matter Research Articles

Exploring the convergence of natural flows for the generation of natural capital stocks in marine ecosystems

Marine ecosystems are open, complex, adaptive, and hierarchical systems highly integrated through the exchange of matter and energy flows. This flows exchange allows marine ecosystems to operate at different scales acting as dissipative structures, building natural capital stocks capable of generating several ecosystem services vital for human well-being. Humans derive a wide range of goods and services from marine ecosystems while, at the same time, generate several impacts causing biodiversity loss and seriously affecting their capacity to provide benefits to humans. Effective management strategies are crucial to conserve healthy and diverse marine and coastal ecosystems, maintain the valuable functions and services they provide, and allow for sustainable human activities. In recent years, Marine Protected Areas (MPAs) have been increasingly acknowledged worldwide as important tools to conserve biodiversity and achieve human well-being and sustainable development goals. Assessing the value of natural capital and ecosystem services is crucial to raise awareness on their importance, support conservation strategies, and ensure the sustainable management of marine ecosystems. This study aimed at calculating biomass and emergy-based indicators to assess the value of natural capital stocks in a Mediterranean MPA. The assessment was performed through a biophysical and trophodynamic environmental accounting model fed with field biomass data collected through ad hoc sampling campaigns performed in the MPA. Four main macro-habitats were investigated: sciaphilic hard bottom (coralligenous bioconstructions), photophilic hard bottom, soft bottom, and Posidonia oceanica seagrass beds. The biomass density of the main autotrophic and heterotrophic taxonomic groups identified in the four macro-habitats of the MPA was evaluated. Based on this biomass matrix, the emergy value of natural capital stocks was assessed. The Posidonia oceanica seagrass beds habitat showed the highest biophysical value (2.32·1019 sej) at MPA scale, while coralligenous bioconstructions resulted the habitat with the highest biophysical value per unit area (2.72·1012 sej m−2). In addition, to complement the biophysical assessment with an economic perspective, the emergy-based indicators were converted into monetary units. The total value of natural capital of the whole MPA resulted in about 46 M€. The results of this study can support local managers and policy makers in the development of management strategies to ensure nature conservation and sustainable human activities. They can be also used as a benchmark for the assessment of natural capital value at larger scales in support of a proper consideration and inclusion of nature value into processes of policy making.

A Framework for Multi-Dimensional Assessment of Wildfire Disturbance Severity from Remotely Sensed Ecosystem Functioning Attributes

Wildfire disturbances can cause modifications in different dimensions of ecosystem functioning, i.e., the flows of matter and energy. There is an increasing need for methods to assess such changes, as functional approaches offer advantages over those focused solely on structural or compositional attributes. In this regard, remote sensing can support indicators for estimating a wide variety of effects of fire on ecosystem functioning, beyond burn severity assessment. These indicators can be described using intra-annual metrics of quantity, seasonality, and timing, called Ecosystem Functioning Attributes (EFAs). Here, we propose a satellite-based framework to evaluate the impacts, at short to medium term (i.e., from the year of fire to the second year after), of wildfires on four dimensions of ecosystem functioning: (i) primary productivity, (ii) vegetation water content, (iii) albedo, and (iv) sensible heat. We illustrated our approach by comparing inter-annual anomalies in satellite-based EFAs in the northwest of the Iberian Peninsula, from 2000 to 2018. Random Forest models were used to assess the ability of EFAs to discriminate burned vs. unburned areas and to rank the predictive importance of EFAs. Together with effect sizes, this ranking was used to select a parsimonious set of indicators for analyzing the main effects of wildfire disturbances on ecosystem functioning, for both the whole study area (i.e., regional scale), as well as for four selected burned patches with different environmental conditions (i.e., local scale). With both high accuracies (area under the receiver operating characteristic curve (AUC) > 0.98) and effect sizes (Cohen’s |d| > 0.8), we found important effects on all four dimensions, especially on primary productivity and sensible heat, with the best performance for quantity metrics. Different spatiotemporal patterns of wildfire severity across the selected burned patches for different dimensions further highlighted the importance of considering the multi-dimensional effects of wildfire disturbances on key aspects of ecosystem functioning at different timeframes, which allowed us to diagnose both abrupt and lagged effects. Finally, we discuss the applicability as well as the potential advantages of the proposed approach for more comprehensive assessments of fire severity.

Formation of intermediate-mass planets via magnetically controlled disk fragmentation

Intermediate mass planets, from Super-Earth to Neptune-sized bodies, are the most common type of planets in the galaxy. The prevailing theory of planet formation, core-accretion, predicts significantly fewer intermediate-mass giant planets than observed. The competing mechanism for planet formation, disk instability, can produce massive gas giant planets on wide-orbits, such as HR8799, by direct fragmentation of the protoplanetary disk. Previously, fragmentation in magnetized protoplanetary disks has only been considered when the magneto-rotational instability is the driving mechanism for magnetic field growth. Yet, this instability is naturally superseded by the spiral-driven dynamo when more realistic, non-ideal MHD conditions are considered. Here we report on MHD simulations of disk fragmentation in the presence of a spiral-driven dynamo. Fragmentation leads to the formation of long-lived bound protoplanets with masses that are at least one order of magnitude smaller than in conventional disk instability models. These light clumps survive shear and do not grow further due to the shielding effect of the magnetic field, whereby magnetic pressure stifles local inflow of matter. The outcome is a population of gaseous-rich planets with intermediate masses, while gas giants are found to be rarer, in qualitative agreement with the observed mass distribution of exoplanets.

Chislennyye eksperimenty po identifikatsii moshchnosti potoka vzveshennogo veshchestva na dne morya v modeli perenosa primesi

The paper deals with variation assimilation of model data on the concentration of suspended matter in the upper layer of the Sea of Azov. Such information is used during practical evaluation of identification algorithms to test the assimilation of concentration values derived from satellite information. Combined use of surface concentration estimates and modeling results based on the transport model is of interest for determining the strength of sources of suspended matter inflow. The test problem has been solved of determination of the required parameter in the sea bottom boundary condition when parameterizing the sediment inflow (agitation) from bottom sediments due to dynamic processes in the sea bottom layer. Two approaches to search for the required constant for the parameterization used in the calculations are implemented. A variational identification algorithm based on adjoint problem solving is used in determining the spatially variable flow of suspended matter on the seabed. The assimilation of measurement data into a model of passive admixture transport allows to determine the spatial structure of such flows at a given time interval. When implementing the variational identification algorithm, gradient methods are used to find optimal estimates by minimizing the quadratic functional of the prognosis quality. The solution of the adjoint problem is used to construct the gradient of the prognosis quality functional. Descent is performed in the direction of this gradient. During realization of variational procedure the main problem, the adjoint problem and the problem in variations, which is necessary to determine an iteration parameter, are solved. The flow fields and turbulent diffusion coefficients used in the calculations were obtained using a dynamic model of the Sea of Azov in sigma coordinates under exposure to intense easterly wind.

Identification of Management Styles with the Use of ICT Support Instruments

Purpose: The article is an attempt to assess the possibilities of selected ICT support tools, in the process of examining the competences and predispositions of the management (command) staff in relation to management styles. Design/Approach: The research was carried out with qualitative methods using STRD thermoregulatory scanning, static eye-tracking and data recording on passive RFID and NFC transponders. The research process concerned a pilot group of students of the Military Academy who were tested in isolated conditions and subjected to the influence of stressors. Findings: The results of the research show that combining the research methodology and enriching it by other analytical devices from the IT group, make it increasingly possible to identify the attitudes of future commanders and managers. The ICT tools used in the research have been enriched during their implementation with new elements. Practical implications: Organizations that want to focus their efforts on priorities such as role modeling, quick decision-making, vision definition or shaping leaders should increasingly use innovative methods of assessing the competences and predispositions of managerial (command) staff not only in the area of decision making. In connection with the above, it is reasonable to strive to develop a holistic model of personality on the basis of which it will be possible to interpret changes in neuroplasticity, and the method of such an examination is the Thermoregulatory Scanning Diagnostics - STRD. Originality/value: Building efficient and at the same time complex ICT support tools for the assessment of managerial and command profiles is becoming one of the elements of the virtual world in the era of increasing intensity of matter, energy and information flows. Augmented reality is increasingly used in many areas of science, economy and medicine, combining the real world and virtual reality with the use of an interactive image in real time.

Ecotrons: Powerful and versatile ecosystem analysers for ecology, agronomy and environmental science.

Ecosystems integrity and services are threatened by anthropogenic global changes. Mitigating and adapting to these changes require knowledge of ecosystem functioning in the expected novel environments, informed in large part through experimentation and modelling. This paper describes 13 advanced controlled environment facilities for experimental ecosystem studies, herein termed ecotrons, open to the international community. Ecotrons enable simulation of a wide range of natural environmental conditions in replicated and independent experimental units while measuring various ecosystem processes. This capacity to realistically control ecosystem environments is used to emulate a variety of climatic scenarios and soil conditions, in natural sunlight or through broad‐spectrum lighting. The use of large ecosystem samples, intact or reconstructed, minimizes border effects and increases biological and physical complexity. Measurements of concentrations of greenhouse trace gases as well as their net exchange between the ecosystem and the atmosphere are performed in most ecotrons, often quasi continuously. The flow of matter is often tracked with the use of stable isotope tracers of carbon and other elements. Equipment is available for measurements of soil water status as well as root and canopy growth. The experiments ran so far emphasize the diversity of the hosted research. Half of them concern global changes, often with a manipulation of more than one driver. About a quarter deal with the impact of biodiversity loss on ecosystem functioning and one quarter with ecosystem or plant physiology. We discuss how the methodology for environmental simulation and process measurements, especially in soil, can be improved and stress the need to establish stronger links with modelling in future projects. These developments will enable further improvements in mechanistic understanding and predictive capacity of ecotron research which will play, in complementarity with field experimentation and monitoring, a crucial role in exploring the ecosystem consequences of environmental changes.

Understanding Multilevel Selection May Facilitate Management of Arbuscular Mycorrhizae in Sustainable Agroecosystems

Studies in natural ecosystems show that adaptation of arbuscular mycorrhizal (AM) fungi and other microbial plant symbionts to local environmental conditions can help ameliorate stress and optimize plant fitness. This local adaptation arises from the process of multilevel selection, which is the simultaneous selection of a hierarchy of groups. Studies of multilevel selection in natural ecosystems may inform the creation of sustainable agroecosystems through developing strategies to effectively manage crop microbiomes including AM symbioses. Field experiments show that the species composition of AM fungal communities varies across environmental gradients, and that the biomass of AM fungi and their benefits for plants generally diminish when fertilization and irrigation eliminate nutrient and water limitations. Furthermore, pathogen protection by mycorrhizas is only important in environments prone to plant damage due to pathogens. Consequently, certain agricultural practices may inadvertently select for less beneficial root symbioses because the conventional agricultural practices of fertilization, irrigation, and use of pesticides can make these symbioses superfluous for optimizing crop performance. The purpose of this paper is to examine how multilevel selection influences the flow of matter, energy, and genetic information through mycorrhizal microbiomes in natural and agricultural ecosystems, and propose testable hypotheses about how mycorrhizae may be actively managed to increase agricultural sustainability.

The role of biota in soil profile formation and soil functioning: new materials and interpretation of well-known facts and existing concepts

Review of the monograph by A.D. Fokin and S.P. Torshin “Plants in the Life of Soils and Terrestrial Ecosystems. Nontraditional Approaches and Solutions on the Behavior of Biologically Significant Elements” published in 2020 by Lap Lambert Academic Publishing, ISBN 978-620-2-53005-7. In the monograph by A.D. Fokin and S.P. Torshin, the reader finds an original and not always traditional for soil scientists, consideration and discussion of a number of fundamental problems of the development of a soil profile and modern soil functioning and of the role of plants and microorganisms in these processes. The authors of the monograph make us think about the validity of some generally accepted concepts and hypothesis, especially those concerning transport flows of matter in soils and their modeling. Attention is drawn to the usually underestimated role of the uplifting – ascending fluxes of matter along the conductive systems of plants, and to the localization of living roots and organic residues in soils. The latter factor plays an important role in the development of intrahorizontal differentiation of the soil material and in the root nutrition of plants. The great advantage of the book is the availability of abundant experimental material obtained by unique methods developed by the authors, simple and effective, which have no analogues in the world literature. Application of these methods, allows, in particular, determining the lifetime of the aggregate in soddy-podzolic soils and establishing the trends in the root uptake of radionuclides from the surface and from the inner part of peds. In the end a general conclusion is formulated that in the course of modern soil functioning, the soil-profile redistribution of matter is performed mainly within the limits of the biological cycle of elements. Many of the problems and ideas discussed in the monograph go far beyond the soil science, therefore the book is of great interest for a wide range of specialists in environmental and plant sciences, in agricultural chemistry, forestry and in various branches of geosciences.

True shape modeling of bio-particulate matter flow in an aero-cyclone separator using CFD–DEM simulation

The multi-phase flow of air and bio-particulate matter exists in many biological and environmental systems such as aerodynamic separating devices, fluidized bed combustion, and feed processing machinery. Integration of the computational fluid dynamics (CFD) and discrete element method (DEM) codes was performed to study bio-particle loading ratios' effect on the cyclone device performance. Every individual particle's behavior was captured by a DEM model using Newton’s equations of motion, in which CFD modeled the continuum airflow for every computational cell scale through the Navier–Stokes equation. According to the high turbulence and chaotic behavior of the continuum airflow inside the cyclone separator, Reynolds stress turbulence model (RSM) was used. The particles used for testing and modeling were conducted on two mixture types of real-heterogeneous particulate matter, namely jojoba seeds and jojoba leaves, without any fly ash. The particles were geometrically modeled using their actual dimensions and shapes, considered the first head start research approach in the cyclonic separation and purification field. The influence of the interacting particle–particle and particle–boundary forces was taken into consideration. The numerical simulation results successfully predicted the cyclone performance at the designed conditions, which showed the best experimental data trend. These data are useful in future studies to modify the cyclone design and optimize bio-systems' operating conditions for separating the macroscopic particulate matter.

To estimation of temperature fluctuations in diamond grains when drilling with diamond bits

Abstract. If we consider the interacting pair: the matrix of a diamond crown, reinforced with protruding diamonds and rock, as a kind of system, then in the process of friction of the matrix against the bottom hole, external mechanical energy is converted into the energy of the heat and matter flows. The main concentration of the flows occurs in places where diamonds protrude above the matrix and take on an additional load. The rubbing system tries to smoothing itself by concentrating pressure and temperature on the diamonds. Diamonds, due to their higher hardness than the destructible medium, are pressed into the rock and destroy it. Since the process of cutting rocks is intermittent, the concentration of energy on diamonds occurs periodically, in the form of “flashes”. Each such “flash” is accompanied by a short-term increase in temperature in the contact zone (temperature fluctuation) and the spalling of a microparticle of the rock. In this work, from the standpoint of thermoelastic instability, the issue of temperature microflashes in single diamonds during the interaction of rough surfaces of the matrix of the diamond crown and the bottom of the borehole is considered, in order to take this factor into account in the mechanism of wear of the diamond of the drill bit. The value of temperature fluctuations on the surface of cutting diamonds was estimated and the size of the flash zone was determined. It is shown that temperature flashes of 400 (С < T* < 3650 (С are observed when drilling granite with a diamond crown on the diamond surface in an area of 5.8(10‑5 m, therefore, the presence of such “microflashes” on the diamond surface in a very small area in the process of interaction with the rock can lead to graphitization of the diamond in this place and separation from the surface of the grain. Such a mechanism should play a certain role in the wear and destruction of diamond surface areas during drilling. The magnitude of temperature fluctuations depends on the physical and mechanical properties of the contacting pair: diamond – rock, operating parameters of the tool and the nature of the placement of diamonds in the crown matrix. In this regard, the study of the assessment of temperature fluctuations in diamond grains when drilling with diamond bits may be of practical interest. Keywords: rock, thermal stresses, intensive cooling, macro- and microcrack system.

On dark stars, galactic rotation curves and fast radio bursts

This paper is a continuation of our recent work on Radial Dark Matter stars (RDM-stars), black holes, coupled with radial flows of dark matter. As a galaxy model, it produces flat rotation curves, approximately valid for many galaxies far from the center. In this paper, more detailed modeling is carried out, including the vicinity of the galactic center. Assuming that the distribution of stellar black holes repeats the distribution of luminous matter, we get a perfect match between the model rotation curves and the observed ones. Further, using numerical integration, we examine the gravitational field of an individual RDM-star. The computation shows the event horizon being erased and rapidly increasing mass density arising instead (mass inflation). In this regime, we apply the previously constructed Planck star model, where at high densities a repulsive force occurs (quantum bounce). In our stationary model, the evolution of a Planck star has stopped under the pressure of dark matter flows. This system is considered as a possible source of Fast Radio Bursts (FRBs). In a scenario involving an asteroid falling onto an RDM-star, the model reproduces the correct frequency range of FRBs. Their total energy, coherence and short duration are explained as well.

Magnetic resonance relaxometry in high-grade glioma subregion assessment - neuroimaging and morphological correlates

To analyze the differences of high-grade glioma subregions using magnetic resonance relaxometry with compilation of images (MAGiC) and arterial spin labeling (ASL), as well as to compare quantitative measurements of these techniques with morphological data. The study enrolled 35 patients with newly diagnosed supratentorial gliomas (23 - grade IV, 12 - grade III). We measured relaxometric values (T1, T2, proton density), tumor blood flow (TBF) in glioma subregions and normal-appearing brain matter. Neuronavigation was intraoperatively used to obtain tissue samples from active tumor growth zone, perifocal infiltrative edema zone and adjacent brain matter along surgical approach. ASL perfusion revealed higher tumor blood flow (TBF) in active tumor growth region compared to perifocal infiltrative edema zone (p<0.01). Relaxometric values (T1, T2, proton density) in perifocal zone were higher (p<0.01) compared to adjacent intact white matter along surgical approach. However, there were no differences in TBF between these zones. Proton density in tumor-adjacent intact white matter was higher (p<0.01) compared to normal-appearing white matter in ipsilateral hemisphere. There was inverse correlation between T2 and TBF in active tumor growth zone (Spearman rank R= -0.58; p=0.0016). We found inverse correlation between T2 and Ki67 proliferative index and direct correlation between TBF and Ki67 in this zone. Nevertheless, these relationships were insignificant after multiple test adjustment. Our study advocates for complementary power of ASL perfusion and MR relaxometry in assessment of high-grade brain glioma subregions. More malignant tumor zones tend to have higher TBF and shorter T2. Further investigation is needed to prove the capability of MAGiC to reveal foci of increased relaxometric values in tumor-adjacent normal-appearing white matter.

Cell Junction Mechanics beyond the Bounds of Adhesion and Tension.

Cell-cell junctions, in particular adherens junctions, are major determinants of tissue mechanics during morphogenesis and homeostasis. In attempts to link junctional mechanics to tissue mechanics, many have utilized explicitly or implicitly equilibrium approaches based on adhesion energy, surface energy, and contractility to determine the mechanical equilibrium at junctions. However, it is increasingly clear that they have significant limitations, such as that it remains challenging to link the dynamics of the molecular components to the resulting physical properties of the junction, to its remodeling ability, and to its adhesion strength. In this perspective, we discuss recent attempts to consider the aspect of energy dissipation at junctions to draw contact points with soft matter physics where energy loss plays a critical role in adhesion theories. We set the grounds for a theoretical framework of the junction mechanics that bridges the dynamics at the molecular scale to the mechanics at the tissue scale.

Ecological Role of Cyprideis torosa and Heterocypris salina (Crustacea, Ostracoda) in Saline Rivers of the Lake Elton Basin: Abundance, Biomass, Production, Fatty Acids.

Saline rivers are highly productive ecosystems in arid regions. The meiobenthic community (bottom meiofauna) and its dominant representatives are one of the least studied components of these aquatic ecosystems. Ostracods Cyprideis torosa and Heterocypris salina are major consumers among the species of bottom meiofauna in saline rivers flowing into the hyperhaline Lake Elton (Volgograd Region, Russia). We estimated the abundance, biomass and production of C. torosa, the dominant species at the mouth of the polyhaline Chernavka River (average salinity is ~30 g l-1), and H. salina, the dominant species at the mouth of the mesohaline Bolshaya Samoroda River (~13 g l-1), in spring (May) and summer (August). Additionally, we studied the composition and content of fatty acids of the ostracods and their potential food sources (bottom sediments with bacterial-algal mats). We found that the abundance and biomass (wet weight with shells) of C. torosa in the Chernavka River and H. salina in the Bolshaya Samoroda River reached 3.5 × 106 ind. m-2 and 117 g m-2, and 1.1 × 105 ind. m-2 and 12 g m-2, respectively. The first species formed on average about 85% of the total abundance and 96% of the total biomass of the meiobenthos, and the second one, about 13% and 31%, respectively. The daily production of C. torosa and H. salina can reach 249 and 36 mg m-2 ash-free dry weight, respectively. The results indicate that these species may play an important role in the total flow of matter and energy in the studied habitats. Based on the fatty acid (FA) composition of the ostracods and their food sources, it was found that C. torosa mainly consumed diatoms, while H. salina preferred bacteria, cyanobacteria, and green algae. Differences between the species were greater than differences between the bottom sediments from the rivers. It may mean that the ostracods selectively consumed different food items that may be related to the different nutrient requirements of the species. Seasonal changes in the FA compositions of the ostracods were higher than in their food sources (bottom sediments), which also indicates selective feeding of the species.

Изменение орбитального периода вспыхивающей двойной системы с учетом ветра от аккреционного диска

We consider a new mechanism for the removal of the angular momentum from an X-ray binary system and the change in its orbital period - the mass loss in the form of a wind from an accretion disc. Both observations and models predict powerful winds from discs in X-ray transients. We have obtained an analytical estimate for the increase in the orbital period of a binary system with a wind from the disc during an outburst, and quantitative estimates are given for the systems XTE J1118+480, A0620-00 and GRS 1124-68. Resulting rate of period grow is of order of the observed rates of secular decrease in the period. We also compare the predicted rate of change in the period of a binary system due to the flow of matter into the disc and outflow from the second Lagrange point with the observations. It is concluded that the above mechanisms cannot explain the observed secular decrease in the period of the three X-ray Novae, and it is necessary to consider a circumbinary disc that drains the binary's angular momentum.

Measurement of the isobar heat capacity of fluids in the critical area by the method of flowing adiabatic calorimeter

With regard to the problem of refining the fundamental equations of state of hydrocarbons, the methodological and design features of the experimental measurement of the isobaric heat capacity in the critical region by the method of a flow adiabatic calorimeter are considered. The pressure measurement system has been improved by introducing a differential manometer into the measuring circuit, which made it possible not only to increase the accuracy of pressure determination, but also to implement a universal scheme of calorimetric experiment. The use of a universal scheme of the calorimetric experiment allows one to determine two values of the isobaric heat capacity at pressures that differ by the value of the pressure loss in the calorimeter. Such an approach in the critical region is relevant, since it makes it possible to quite simply and reliably determine the value of the derivative of the heat capacity with respect to pressure, which is used to estimate not only the error in assigning the value of heat capacity to pressure, but also the equilibrium conditions of the experiment in a flow-through calorimeter. The technique of determining and making a correction for the inhomogeneity of the supply wires of the differential thermocouple, for the throttling of the flow of matter in the calorimeter is considered. Correct relations are obtained for determining the average temperature of the measurement experiment for various methods of measuring the temperature and temperature difference in a flow-through calorimeter. The results of experimental measurements of the isobaric heat capacity of n-pentane in the critical region, obtained using the universal scheme of the calorimetric experiment, for n-pentane were measured on an isobar of 3.400 MPa (critical pressure 3.355 MPa), which is the closest to the critical point at practice of flow calorimetry

Rheological Characteristics of Dammar Mata Kuching

Rheology is already defined as the science of flow and deformation of matter. The purpose of rheology is to look at the relationships between stress and deformation of the material-marterial (non-Newtonian) in order to explain its mechanical properties. One of the ingredients that is often used as a basic material for making products is dammar. Dammar is a general term used to name a material in the form of natural resin which is the result of exudation of trees from the Dipterocarpaceae and Burseraccae families. This research uses raw materials dammar and toluene which are used to make a solution of dammar with the proportion of dammar: toluene, namely 50: 50, 40: 60, 35: 65, and 30: 70. Then the rheological analysis is analyzed by measuring the viscosity value, the shear rate. , and also its shear stress. The viscosity value increases with the greater the shear rate and the value of n (Flow Behavior index) is&gt; 1, indicating that a solution of resin is a fluid with a type of dilatan fluid.&#x0D; &#x0D; Keywords: dammar, deformation, rheology, shear rate, shear stress.

Spatial homogenization of understorey plant communities under eCO2 in a mature Eucalyptus woodland

Abstract Understorey plant communities comprise a large portion of biodiversity of forests and woodlands globally, where they contribute to tree species dynamics, biogeochemical cycling and carbon sequestration. Here we evaluated the effects of elevated CO2 (400 vs. 550 ppm) on the spatial distribution of understorey plant communities from a mature eucalypt woodland in Eastern Australia (EucFACE experiment). Three years of elevated CO2 resulted in a loss of the characteristic aggregated and segregated spatial pattern of species richness at both short and long distances (20 cm–227 cm), respectively. Changes in spatial patterns emerged over time, indicating that these results are due to a relatively slow reordering of the understorey plant community. In contrast, when analysed from a multivariate perspective, changes in terms of community composition were not as clear as changes in the spatial rearrangement of plant communities. Synthesis. Given that the spatial patterns of communities are likely a reflection of the way in which multiple species interact and how energy and matter flow throw ecosystems, community reordering due to global change may have far‐reaching implications in terms of ecosystem functioning. Moreover, subtle early changes in the spatial pattern of understorey plant communities may represent an early‐warning indicator of global change impacts in forest ecosystems.

Numerical Simulation of the Distribution of In Situ Cigarette Combustion-Generated Particulate Matter

This paper has established a two-dimensional (2D) mathematical model for the generation, growth, and deposition of cigarette total particulate matter (TPM) in the smoldering state. The model has covered the chemical reactions and mass transfer as well as the mechanism of generation, flow, and condensation of particulate matter inside a burning cigarette. Cigarette smoke was generated by puffing under a constant pressure, and the pressure of the filter outlet was −274 Pa. The peak of the concentration of particulate matter was spatially overlapped with the peaks of pyrolysis and oxidation. Pertaining to the cross section of the cigarette at the same axial position, the peak of the diameter of particulate matter along the radial distribution first appeared in the zone near the edge of the cigarette cross section, and then gradually moved to the center of the cigarette with the cigarette smoke moving away from the combustion cone. The maximum number density of particulate matter calculated by the 2D mathematical model at the same axial position of the cigarette and the corresponding particle diameter, as well as the filtration efficiency of the filter rod, are in good accordance with the experimental data reported in previous studies.

Bioenergetic traits of three keystone marine species in the food web of a pristine Patagonian fjord

The Patagonian fjords are high-latitude aquatic ecosystems, highly sensitive to climate change and play a key role in the exchange of organic matter and carbon flows between terrestrial and marine environments. The bioenergetic composition of species living in these ecosystems are fundamental to understanding the distribution, seasonal variations, and exchange of organic matter within benthic communities. This study reports on the bioenergetic characteristics (lipids, protein, glucose, and energy content) of three keystone species with different life-style and feeding habits: a benthic sea star (Ctenodiscus australis); squat lobster (Munida gregaria); and a Patagonian notothenioid (Eleginops maclovinus). Samples were obtained from the Yendegaia Fjord (54°40'S - 68°50′W) in Chilean Patagonia. Our results indicate that M. gregaria has higher concentrations of lipids, proteins, glucose, and total energy compared to either E. maclovinus or C. australis. The predominance of lipids in all species is possibly related to physiological characteristics and feeding strategies. Also, may be associated with the availability of food and environmental conditions typical of a fjord ecosystem and the reproductive stage in that they were collected. These results suggest that marine animals inhabiting glacially influenced environments with low temperature and low productivity, requires a convergent physiological strategy characterized by high levels of energy storage (i.e. lipids) for metabolism and key bioenergetic processes such as growth and reproduction.