scholarly journals Thermodynamics of the evolution of the biosphere

2022 ◽  
Vol 962 (1) ◽  
pp. 012032
Author(s):  
A B Ptitsyn
Keyword(s):  
Water Content ◽  
Natural Waters ◽  
Nonequilibrium Thermodynamics ◽  
External Factors ◽  
Stable States ◽  
Natural Systems ◽  
Complex Indicators ◽  
Land Hydrology

Abstract The thermodynamic foundations of the evolution of the biosphere are considered: the variability of natural systems with different dispersion of their components, the alternative ways of development of such systems, the alternative of intermediate stable states of ecosystems depending on fluctuations of external factors, primarily climate. The necessity of developing a system of mutually agreed complex indicators of this process is postulated. The necessity of including the water content of ecosystems in the number of parameters of nonequilibrium thermodynamics is justified. A new section of land hydrology is formulated -the study of thermodynamic aspects of the dynamics of natural waters.

Biodegradation studies as an important way to estimate the environmental fate of chemicals

1999 ◽  
Vol 39 (10-11) ◽  
pp. 375-382
Author(s):  
Andreja Žgajnar Gotvajn ◽  
Jana Zagorc-Končan
Keyword(s):  
Surface Waters ◽  
Natural Waters ◽  
Environmental Fate ◽  
Standard Test ◽  
Screening Tests ◽  
Natural Systems ◽  
Additional Information ◽  
Assessment Tests ◽  
Ready Biodegradability ◽  
Biodegradability Assessment

Biodegradation is confirmed as an important mechanism of organic chemicals removal in natural systems. Estimation of biodegradability of chemicals which reach the aquatic environment in significant or even negligible quantities is necessary in assessing the entire hazard associated with their use. The aim of our study was to compare the standardized ready biodegradability assessment test (closed bottle test) and its modifications, employing the basic agreements on test principles of simulation of biodegradation in surface waters, yet no official standard method has been adopted. The standard test was modified using various natural river waters and a variety of nutrient conditions and microbial species trying to simulate the natural environment in the simplified way. Tests were performed with two compounds with different ability to degrade. Experiments indicate that predictability of biodegradation obtained by ready biodegradability assessment tests for surface waters in many cases is not reliable, because of different conditions, which may prevail in surface waters over time and affect biodegradation. However, the use of natural waters in screening tests assures additional information on fate of chemicals in rivers and lakes.

Geochemical modelling of arsenic release into the crystalline aquifers: preliminary study

2021 ◽  
Author(s):  
Ilaria Fuoco ◽  
Rosanna De Rosa ◽  
Carmine Apollaro
Keyword(s):  
Natural Waters ◽  
Geochemical Modeling ◽  
Analytical Data ◽  
Arsenic Concentration ◽  
Primary Source ◽  
Limited Area ◽  
Rock Interaction ◽  
Natural Systems ◽  
Calabria Region ◽  
Crystalline Aquifer

<p>Arsenic (As) is a toxic element present in different natural systems. The aqueous As species and their concentrations in natural waters depend on a variety of parameters, including the presence of natural source and the local geochemical conditions. The primary source of As in natural waters is the oxidation of mineral sulphides like arsenopyrite (FeAsS) and As-rich pyrite (FeS<sub>2</sub>) [1]. The trivalent iron (Fe<sup>3+</sup>) can act as oxidant for pyrite oxidative dissolution together with dissolved oxygen.In this work the attention is focused in As- contaminated area of the Calabria Region (Southern Italy). The high arsenic concentration is a peculiar characteristic of the shallow groundwaters circulating in a limited area of the Calabria region, which represents an unexplored mineralized area. Indeed, although pyrite is widely present in the crystalline rocks, its spatial distribution is highly variable and not predicable [2]. Generally, the As content of the studied granite rocks is within the normal global range but the presence of not-surfacing, hydrothermally-altered granites, could be the cause of As contamination in limited areas.  In order to explain the As-rich groundwaters occurring into crystalline aquifer, a reaction path modelling of granite dissolution was performed by using EQ3/6 software package version 8a.  The dissolving granite was considered to be constituted by quartz, two types of plagioclase (representing the rim and the core of the mineral), K-feldspar, biotite, muscovite, chlorite, epidote, fluorapatite and pyrite.  The considered value of pyrite content and its As concentration fall within the global estimations [3]. Two simulations were performed allowing the precipitation of moganite, gibbsite, kaolinite, illite-py and the calcite-rich solid solution of trigonal carbonate. Moreover, two oxy-hydroxide solid solutions composed of amorphous Fe(OH)<sub>3 </sub>- amorphous ferric arsenate and 2 lines-ferrihydrite - scorodite were precipitated in two separate runs to evaluate their effects on dissolved As. Nine water samples were used to fix the boundary conditions as well as to validate the outcomes of geochemical modeling. The arsenic concentration detected ranging from 25 to 435 µg/L. The theoretical trend involving the precipitation of amorphous Fe(OH)<sub>3</sub> is in agreement with the groundwaters richest in As, because a higher amount of pyrite is dissolved due to a greater availability of trivalent Fe in the aqueous solution, which is caused by the higher solubility of amorphous Fe(OH)<sub>3</sub> compared to 2-line ferrihydrite. The analytical data of the As-rich groundwaters, as a whole, are well explained by the performed simulations, suggesting that these processes control the release and fate of arsenic during the water-rock interaction.</p><p> </p><p>[1]. Sracek, O., Bhattacharya, P., Jacks, G., Gustafsson, J. P., & Von Brömssen, M. ,2004. Behavior of arsenic and geochemical modeling of arsenic enrichment in aqueous environments. Applied Geochemistry, 19(2), 169-180.</p><p>[2]. Bonardi G., De Vivo B., Giunta G., Lima A., Perrone V., Zuppetta A., 1982. Mineralizzazioni dell’Arco Calabro Peloritano.Ipotesi genetiche e quadro evolutivo. Boll.Soc.Geol.It. 101</p><p>[3]. Smedley, P. L., & Kinniburgh, D. G.,2002. A review of the source, behaviour and distribution of arsenic in natural waters. Applied geochemistry, 17(5), 517-568.</p>

scholarly journals Inferring Models with Alternative Stable States from Independent Observations

2020 ◽  
Author(s):  
Edward W. Tekwa ◽  
Martin Krkošek ◽  
Malin L. Pinsky
Keyword(s):  
Initial Conditions ◽  
Alternative Stable States ◽  
Ecological Systems ◽  
Process Models ◽  
Stable States ◽  
Multiple Attractors ◽  
Natural Systems ◽  
Social Ecological Systems ◽  
Social Ecological ◽  
Independent Observations

AbstractMultiple attractors and alternative stable states are defining features of scientific theories in ecology and evolution, implying that abrupt regime shifts can occur and that outcomes can be hard to reverse. Here we describe a statistical inferential framework that uses independent, noisy observations with low temporal resolution to support or refute multiple attractor process models. The key is using initial conditions to choose among a finite number of expected outcomes using a nonstandard finite mixture methodology. We apply the framework to contemporary issues in social-ecological systems, coral ecosystems, and chaotic systems, showing that incorporating history allows us to statistically infer process models with alternative stable states while minimizing false positives. Further, in the presence of disturbances and oscillations, alternative stable states can help rather than hamper inference. The ability to infer models with alternative stable states across natural systems can help accelerate scientific discoveries, change how we manage ecosystems and societies, and place modern theories on firmer empirical ground.

Dynamic features of speciation analysis by adsorptive stripping techniques

2010 ◽  
Vol 7 (3) ◽  
pp. 242 ◽  
Author(s):  
Raewyn M. Town ◽  
Herman P. van Leeuwen
Keyword(s):  
Ligand Exchange ◽  
Natural Waters ◽  
Environmental Fate ◽  
Metal Speciation ◽  
Speciation Analysis ◽  
Dynamic Features ◽  
Natural Systems ◽  
Surface Active ◽  
The Stability ◽  
Kinetic Features

Environmental context.The environmental fate and bioavailability of metal ions in natural waters is determined by their thermodynamic stability and kinetic features, both of which are distributed. Competing ligand exchange – adsorptive stripping (CLE-AdS) is a technique that measures a certain portion of these complexes as determined by the stability of the selected competing ligand and the dynamic features of the sample complexes that remain following ligand exchange. Exploitation of CLE-AdS to determine a spectrum of sample complexes requires insight into its thermodynamic and kinetic windows. Abstract.The kinetic features of the accumulation step of competing ligand exchange – adsorptive stripping (CLE-AdS) in metal speciation methodology are elaborated. During the adsorptive accumulation process, the flux of the surface active complex MLad towards the electrode may be modified by the coupled conversions of ML and M into MLad. An immediate consequence is that the accumulation flux of MLad can be greater than that corresponding to its mere bulk concentration: a labile ML contributes fully to the MLad accumulation, and a further flux enhancement can arise if ML is more mobile than MLad (DML > DMLad). Applying the conventional lability criterion, we present a framework for interpretation of CLE-AdS measurements in the presence of kinetic contributions from sample ML to the adsorptive accumulation of MLad. Measured accumulation fluxes for a kinetic case are well described by the presented theoretical framework. The dynamic analysis provides the basis for exploitation of CLE-AdS over a wider kinetic window than has been used to date. Consideration of the dynamics of sample species during the adsorptive accumulation step is fundamental for interpretation of metal speciation by CLE-AdS in complex natural systems that contain a distribution of complexes of different stability, lability, and mobility.

Postscript: the future history of the garden

2019 ◽  
pp. 133-136
Author(s):  
Gordon Campbell
Keyword(s):  
Climate Change ◽  
Disease Control ◽  
External Factors ◽  
Garden Design ◽  
Natural Systems ◽  
Impact Of Climate Change ◽  
Soil Enrichment ◽  
The Future ◽  
History Of ◽  
Organic Gardening

Planting and garden design have never stood still, in part because fashions change, but also because of external factors. The most conspicuous fashion in recent decades has been the rise of organic gardening, a movement originating in the 1920s, which aspires to sustainability achieved by a synergy with natural systems of soil enrichment and pest and disease control. Another driver of change is the reduction in biodiversity. The Postscript considers the likely impact of climate change on garden design and suggests gardens will continue to evolve, as they have since remote antiquity. Garden design will adapt to changing conditions, but gardens will continue to provide havens of beauty and respite for the weary.

Multiple Stable States and Catastrophic Shifts in Ecosystems

Ecology ◽  
2019 ◽  
Author(s):  
Sonia Kéfi
Keyword(s):  
Alternative Stable States ◽  
Direct Consequence ◽  
Theoretical Models ◽  
Economic Consequences ◽  
Design Management ◽  
Stable States ◽  
Natural Systems ◽  
Restoration Strategies ◽  
Multiple Stable States ◽  
Catastrophic Shifts

The idea that ecosystems may have multiple alternative stable states dates back to the late 1960s–early 1970s, when ecologists realized that this type of behavior could arise in simple mathematical models. A direct consequence is that such ecosystems can suddenly switch (or “tip”) between their alternative stable states rather than gradually responding to changes. In other terms, in these ecosystems, a small environmental perturbation can cause large, discontinuous, and irreversible changes, referred to as catastrophic shifts. This idea has attracted increasing interest in the literature over the years, and has become even more relevant in the current context of global change. Examples of catastrophic shifts in ecosystems include the eutrophication of shallow lakes, the desertification of drylands, and the degradation of coral reefs. Theoretical models have investigated the conditions under which alternative stable states and catastrophic shifts occur. A well-recognized cause of alternative stable states is the presence of strong positive—or self-reinforcing—feedback processes that maintain each of the stable ecosystem states. Understanding the mechanisms underlying the emergence of alternative stable states can help design management as well as restoration strategies for ecosystems. Because catastrophic shifts can have dramatic ecological and economic consequences, approaches have been proposed to detect possible alternative stable states in natural systems, and indicators of approaching ecosystem transitions have been identified (so-called early warning signals of critical slowing down).

scholarly journals The excystation of colpoda cucullus from its resting cysts, and the nature and properties of the cyst membranes

1913 ◽  
Vol 86 (589) ◽  
pp. 427-439 ◽  
Keyword(s):  
Water Content ◽  
Food Supply ◽  
External Factors ◽  
External Influences ◽  
Determining Factors ◽  
Resting Cysts ◽  
Working Out ◽  
Considerable Detail ◽  
The Way

Having had occasion to make use of the resting cysts of Colpoda cucullus in the course of my work on the protozoa of the soil I was interested by the way in which the organisms escape from the confines of the cyst membranes. The processes involved were by no means obvious on somewhat casual observation, and it became necessary to study them in considerable detail before they could be fully elucidated. Moreover it was thought by working out as fully as possible the conditions involved in excystation some light might be thrown on the activity or inactivity of the protozoa in the soil. The water-content, available food supply, and temperature of any soil are obvious external factors in determining the possibility of protozoal activity, but that these were all the determining factors was by no means clear. There was the possibility that certain peculiar external influences were required for excystation, and if these could be determined it was possible that one would be able to say whether they were present or absent in a soil normally containing protozoa.

scholarly journals Questions of size and numbers in environmental research on microplastics: methodological and conceptual aspects

2015 ◽  
Vol 12 (5) ◽  
pp. 527 ◽  
Author(s):  
Montserrat Filella
Keyword(s):  
Natural Waters ◽  
Surface Characteristics ◽  
Theoretical Background ◽  
Environmental Research ◽  
Natural Systems ◽  
Density Surface ◽  
The Subject ◽  
The Impact ◽  
Particles And Colloids ◽  
Environmental Compartments

Environmental context Microplastics, either purposefully manufactured or formed by fragmentation of discarded ‘end-of-life’ macroplastic items, are accumulating in environmental compartments. As more and more data are collected on microplastics in the environment, discussion of two issues has become indispensable: (i) how reliable are the results in terms of the inherent capabilities and limitations of current methods used for sampling, counting and measuring microplastic particles; and (ii) how can the fate of microplastics be understood in the context of natural particles and colloids? Abstract A first important step in evaluating the impact of microplastic pollution in natural systems is assessing the reliability of the results obtained according to the inherent capabilities and limitations of the methods used for sampling, counting and measuring microplastic particles. This study, based on the critical reading of 55 studies containing quantitative microplastic data in waters and sediments, is an attempt to analyse these issues in the light of existing knowledge in the field of natural colloid studies. Existing results are highly dependent on the sampling and methodological procedure chosen and are essentially descriptive. Moreover, often they lack standardisation and adequate reporting of basic information such as the meaning of the size parameter measured. Colloid theory may provide the theoretical background needed to explain microplastic behaviour or, at least, to identify the parameters (e.g. density, surface characteristics, shape) that need to be known in order to gain a predictive knowledge of the subject. They are introduced and discussed. Finally, microplastics are not alone in environmental compartments. For this reason, when possible, published microplastic particle size distributions in natural waters have been quantitatively situated in the context of natural particles.

scholarly journals Currently Observed Hydrological Regime and Channel Processes of the Ufa River Downstream in the within the City of Ufa Water Intakes Area

2018 ◽  
Author(s):  
Keyword(s):  
Water Content ◽  
River Water ◽  
Water Intake ◽  
Hydrological Regime ◽  
External Factors ◽  
Urban Water ◽  
Channel Processes ◽  
River Level ◽  
The City ◽  
Level Lowering

General characteristics of the Ufa River downstream and the city of Ufa water intakes are given. Current hydrological regime and channel processes of the Ufa River downstream have been studied in the Ufa urban water intakes area through the outcomes of the comprehensive detailed investigations of three reaches in the 2016–2017 period, namely, reach 1: the Northern Infiltration water intake area, the Northern Plunge water intake area, and the Shaksha water intake area; reach 2: TPP-2 water intake area; and reach 3: the southern infiltration water intake area. The regularities of the Pavlovsk reservoir impact upon the current hydrological regime of the said reaches have been stated. We have analyzed the Ufa River level lowering dynamics at the Shaksha water gauging post over the period from 1961 to 2017. We compared changes of the level incurred by external factors and by the river water content and we have found the causes of these level changes.

Physical Properties and Gradients

2006 ◽  
Author(s):  
Thomas S. Bianchi
Keyword(s):  
Internal Energy ◽  
Natural Waters ◽  
Chemical Constituents ◽  
Homogeneous Distribution ◽  
Equilibrium Models ◽  
Fixed Temperature ◽  
Aquatic Chemistry ◽  
Natural Systems ◽  
Chemical Systems ◽  
Constrained Conditions

Before discussing the chemical dynamics of estuarine systems it is important to briefly review some of the basic principles of thermodynamic or equilibrium models and kinetics that are relevant to upcoming discussions in aquatic chemistry. Similarly, the fundamental properties of freshwater and seawater are discussed because of the importance of salinity gradients and their effects on estuarine chemistry. Stumm and Morgan (1996) described how different components of laboratory- and field-based measurements in aquatic chemistry are integrated. Basically, observations from laboratory experiments are made under well-controlled conditions (focused on a natural system of interest), which can then be used to make predictions and models, which are ultimately used to interpret complex patterns in the natural environment. Due to the complexity of natural systems, equilibrium models can tell you something about how chemical constituents (gases, dissolved species, solids) under well-constrained conditions (no change over time, fixed temperature and pressure, and homogeneous distribution of constituents). Equilibrium models will tell you something about the chemistry of the system at equilibrium but will not tell you anything about the kinetics with which the system reached equilibrium state. The laws of thermodynamics are the foundation for chemical systems at equilibrium. The basic objectives in using equilibrium models in estuarine/aquatic chemistry is to calculate equilibrium compositions in natural waters, to determine the amount of energy needed to make certain reactions occur, and to ascertain how far a system may be from equilibrium (Stumm and Morgan, 1996). The first law of thermodynamics states that energy cannot be created or destroyed (i.e., the total energy of a system is always constant). This means that if the internal energy of a reaction increases then there must be a concomitant uptake of energy usually in the form of heat. Enthalpy (H) is a parameter used to describe the energy of a system as heat flows at a constant pressure; it is defined by the following equation: . . . H = E + PV (4.1) . . . where: E = internal energy; P = pressure; and V = volume.

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