Trends in entropy production during ecosystem development in the Amazon Basin

Abstract

Understanding successional trends in energy and matter exchange across the ecosystematmosphere boundary layer is an essential focus in ecological research; however, a general theory describing the observed pattern remains elusive. This paper examines whether the principle of maximum entropy production could provide the solution. A general framework is developed for calculating entropy production using data from terrestrial eddy covariance and micrometeorological studies. We apply this framework to data from eight tropical forest and pasture flux sites in the Amazon Basin and show that forest sites had consistently higher entropy production rates than pasture sites (0.461 versus 0.422 W m 22 K 21 , respectively). It is suggested that during development, changes in canopy structure minimize surface albedo, and development of deeper root systems optimizes access to soil water and thus potential transpiration, resulting in lower surface temperatures and increased entropy production. We discuss our results in the context of a theoretical model of entropy production versus ecosystem developmental stage. We conclude that, although further work is required, entropy production could potentially provide a much-needed theoretical basis for understanding the effects of deforestation and land-use change on the land-surface energy balance.

It is not the entropy you produce, rather, how you produce it

“…How exactly this postulated process of integrating the future works is still to be elucidated, but obviously if true, it holds the potential of yoking natural selection to entropy selection, and is along the lines of our challenge for MEP theory to deal with the 'how' of entropy production. Holdaway et al (2010) also see the challenge, as they suggest 'three different MEP selection pressures at work during ecosystem development,' and discuss constraints, such as nutrient limitations during later periods in ecosystem succession. Obviously MEP theory is not going to be able to postulate a single holistic calculation that can simply be applied across the boards of physical-chemical and biological systems.…”

Maximum entropy production in environmental and ecological systems

“…The last six papers deal with various aspects of biotic organisms, ranging from the scale of bacteria (Ž upanović et al 2010) and ecosystems (Holdaway et al 2010;Schymanski et al 2010 Schymanski et al ). Ž upanović et al (2010 take a thermodynamic view of bacterial chemotaxis-the ability of some bacteria to direct their movement towards certain chemicals such as glucose.…”

“…He suggests that the statistical interpretation of MEP offers a new paradigm for biological evolution of the 'survival of the likeliest', which applies to groups of cells and ecosystems, not just individuals. Holdaway et al (2010) develop a general framework to calculate entropy production from eddy covariance and micrometeorological observations. Using field data from Amazonian forests and pastures, they find that, during forest development, the changes in vegetation properties, such as a lower canopy albedo and deeper rooting depths, result in cooler surface temperatures and higher rates of entropy production.…”

“…Several of these are related to energetic properties, such as minimum stream power, minimum energy dissipation, maximum friction and minimum energy expenditure. In order to evaluate the validity of these apparently contrasting optimality approaches, they suggest that these approaches should accommodate for the dynamic nature of the system (such as hydrologic variability) and take a broader view that accounts for complex feedback processes with atmospherical, biological and geological processes.The last six papers deal with various aspects of biotic organisms, ranging from the scale of bacteria (Ž upanović et al 2010) and ecosystems (Holdaway et al 2010;Schymanski et al 2010 Schymanski et al ). Ž upanović et al (2010 take a thermodynamic view of bacterial chemotaxis-the ability of some bacteria to direct their movement towards certain chemicals such as glucose.…”

Radiative Entropy Production along the Paludification Gradient in the Southern Taiga

“…To calculate entropy production and the empirical maximum of entropy production (EMEP), we used the technique from Stoy et al [14]. This method is based on quantifying entropy production following Brunsell et al [22] and using the approach of Holdaway et al [31]. It requires data on the air temperature and on short-wave incoming (Q S,in ), short-wave outgoing (Q S,out ), long-wave incoming (Q L,in ), and long-wave outgoing (Q L,out ) radiation.…”