Analysis Of Environmental Processes Research Articles

Molecular weight driving bioavailability and intrinsic degradation mechanisms of dissolved organic phosphorus in lake sediment

The sediment dissolved organic phosphorus (DOP) for the “internal phosphorus (P) loading” has raised intensive concern, but its bioavailability and intrinsic degradation mechanism have not been fully elucidated. In this work, multi-techniques were combined to construct the response of sediments DOP's bioavailability to molecular weight (MW) based on ten lakes of China, thereby elucidating the intrinsic degradation mechanism of sediment DOP. A high percentage (74.5% on average) and significantly positive correlations with respect to different MWs were observed, highlighting the importance of DOP to dissolved P in sediments. DOP is mainly composed of a low MW (LMW) portion (63.8%) and the substances are primarily derived from microbial sources. Bioavailable DOP species were closely related to MW, with labile monoester P and diester P decreased with decreasing MW. Analysis of environmental processes showed that microbial utilization capacity and the characteristics of dissolved organic matter (DOM) with different MWs were the dominant drivers in determining the bioavailability of DOP. That is, microorganisms exhibit high DOM utilization capacity in LMW portion, promoting the degradation and transformation of bioavailable DOP species. Furthermore, the increased humic and fulvic-like substances by microbial degradation might in turn inhibit the enzymatic hydrolysis of LMW-DOP. This pattern explains why the contents of LMW-DOP are very high, but it contains less bioavailable DOP. By studying the bioavailability of sediment DOPs with different MWs, it is found that, under natural conditions, labile monoester and diester P in LMW-DOP have a high tendency to degrade than those in HMW-DOP. The results further show that, microbial utilization and DOM characteristics, as well as their linkage with DOP's bioavailability and degradability, have important implications for assessing DOP's degradation potential. The insights from this study might shed light on more effective strategies for mitigating the risks of "internal P loading".

Influence of exposure time on phosphorus composition and bioavailability in wetland sediments from Poyang lake, since the operation of the Three Gorges Dam

The role of exposure time on wetland sediment-bound phosphorus (P) biogeochemical behavior is studied in Lake Poyang after the operation of the Three Gorges Dam (TGD). The multiple P compounds primarily include orth–P (88.3%), mono–P (8.9%), DNA–P (2.1%), and pyro–P (0.8%) in the exposed sediments. A significant decreasing trend of orth–P occurred after the operation of the Three Gorges Dam (TGD), with the mean concentration decreasing from 175.9 to 142.5 mg kg−1 from 2007 to 2012 (ANOVA: P < 0.05), whereas the temporal change in biogenic P showed great variability. The plant distribution pattern and the increase in plant biomass due to decreased water levels might be the reason that caused variations in the P species. Furthermore, the content of orth–P, mono–P, DNA–P, and pyro–P showed increasing trends as sediment exposure time increased. However, the enzyme hydrolysis rate of DNA–P decreased with exposure time and may cause the bioavailability of biogenic P to decrease. Despite the fact that the bioavailability of biogenic P might decline in the short term, the favorable environmental conditions for P release in sediment rewetting processes, together with the increase in orth–P and biogenic P due to extended exposure time, indicate that these large additions of P would enter the overlying water and cause water quality decline once the sediment is submerged underwater during the next wet season. An environmental process analysis showed that the increased exposure time induced sediment environmental conditions changes that played an important role in the biogeochemical cycle of P and may be an important way of P replenishment in Lake Poyang. The results of this study help provide a better understanding of the role of sediment drying/wetting cycles in nutrient biogeochemical behavior and fates in wetland ecosystems.

Internet of Things: Architectural Components, Protocols and Its Implementation for Ubiquitous Environment

Ubiquitous data processing of the sensing nodes has revolutionized the development of electronic industries manufacturing. The concept of the Internet of Things (IoT) is the connectivity of distributed sensing and processing nodes from anywhere rather than fixed computing. For the Implementation of Ubiquitous smart environment, anything and everything can be converted to smart IO Things, and where things have sensing and processing abilities for automation and analysis of environmental processes. Sensors, actuators, embedded processing systems, networking gateways, and IoT Cloud Services are the building blocks of IoT implementation. This paper presents a brief discussion on the connectivity of building blocks with various enabling technologies for the implementation of the Internet of Things. Moreover, many of data link standards and the internet of things data communication protocols will be in the discussion.

Web-based GIS technologies for monitoring and analysis of spatio-temporal processes

Purpose This paper aims to describe two Web-based technologies of geographic information systems (GIS) to be used in monitoring and analysis of environmental processes, proposed by the authors. The technologies analyze the temporal aspect of the process together with the spatial aspect, which defers them from most other works on environmental processes, as these are usually limited either to spatial statistics or to temporal statistics. The approach is instrumental in dynamically finding the relationships between the processes and predicting critical incidents. Design/methodology/approach Often, the study of natural processes is limited to the analysis of their spatial properties presented by individual time series. The principal idea of this approach consists in supplementing this traditional analysis with the analysis of time fields. In this way, the authors are able to analyze temporal and spatial properties of environmental processes together. Findings The paper presents two technologies which provide the analysis of spatial and temporal data obtained in natural environment monitoring. The discussed spatio-temporal data mining methods are shown to enable the research into environmental processes, and the solution of practical issues of critical situation forecasts. Originality/value The paper discussed Web-based GIS technologies for the analysis of the temporal aspect of the environmental process together with the spatial aspect. Application examples demonstrate the ability of this approach to find the relationships in dynamics of the processes and to predict critical incidents.

Numerical methods and fuzzy parameters: an environmental impact assessment in aquatic systems

This paper proposes to analyze the dispersion of pollutants in aquatic systems, solving the advection–diffusion equation using numerical methods and fuzzy sets. For solution, numerical approximations were adopted, based on the finite element method for the spatial discretization and Crank–Nicolson for the time variable. The parameters of the equation were modeled taking into account aspects of multiple varieties of natural phenomena, based on fuzzy sets. The two-dimensional model resulted in the value of pollutant dispersion taking into account the flow velocity, in situations of prevailing winds in the region of a reservoir of Sao Paulo. According to the results, it was observed that the integration of the numerical methods and the fuzzy parameters is a potential instrument for environmental process analysis. The rule-based systems allowed a better design of the local natural phenomena. The spread of the plumes of pollutants was well defined by the model and the simulated scenarios are in agreement, from a qualitative point of view, with the local reality.

Scaling Down the Analysis of Environmental Processes: Monitoring Enzyme Activity in Natural Substrates on a Millimeter Resolution Scale

Natural environments often show high levels of spatial heterogeneity. With a methodology based on the immobilization of fluorescent substrates, the distribution of extracellular enzymes can be studied at a 2.3-mm resolution with a detection limit of 1.8 nmol · h(-1) · cm(-2). The method is applicable to environmental samples such as wood, litter, soil, or fungal colonies.

Environmental Process Analysis, 2: Dynamic Steady States

Environmental analysis requires an understanding of processes that contribute to a system and the concept of dynamic balances. The Conservation of Mass (Heat) equation for a system determines whether (e.g.) concentration (heat) in the system will increase, decrease or remain constant. The rate at which change occurs in a system and the magnitude of that change are functions of the dynamic balance and the rate constants (residence times−1) for individual processes. We express this mass (heat) balance concept as a simplified algebraic expression (“IPOLA”) and use it to evaluate the dynamics of systems. We present a classroom activity that can be accomplished in a short time with minimal cost to demonstrate these principles. Our experience suggests that this activity and the “IPOLA” equation build knowledge by developing a conceptual understanding of systems and their component processes.

Environmental Process Analysis, 1: Residence Time and First Order Processes

The environment is a system of coupled physical, chemical and biological processes that yield either a change in the state of the system or a dynamic steady-state. The conservation of mass equation is used to quantify such dynamic systems and is presented here with the acronym ‘IPOLA’. The time scale for a change in state of a system can be understood with the concept of residence time. We describe a simple salt flushing laboratory activity that allows detailed investigation of rates, processes and principles of dynamic systems for both the algebra-skilled student and the minimal-calculus prepared (high school and university) student. The activity focuses on the calculation and use of the residence time as a fundamental principle defining rates-of-change in systems (“How long will it take to…?”). The ‘rules-of-thumb’ (time to change by 50%, time to change by 95%) and simple estimates that can be made from real data (concentration vs. time) generated by this activity provide a useful starting point for the evaluation of the environment as a dynamic process with inherent timescales for change. Students are also introduced to conversion factors, instrument correction factors, analysis of real data and a problem solving approach based on ‘IPOLA’.

Review of Environmental fluid mechanics by Hillel Rubin and Joseph Atkinson

Review of <i>Environmental fluid mechanics</i> by Hillel Rubin and Joseph Atkinson