Bridging the gap between empirical and mechanistic models of aquatic primary production with the metabolic theory of ecology: An example from estuarine ecosystems

2012 ◽  
Vol 233 ◽  
pp. 83-89 ◽  
Author(s):  
Lora A. Harris ◽  
Mark J. Brush
Keyword(s):  
Primary Production ◽  
Mechanistic Models ◽  
Metabolic Theory ◽  
Metabolic Theory Of Ecology ◽  
Estuarine Ecosystems ◽  
Empirical And Mechanistic Models

The Metabolic Theory of Ecology

2017 ◽  
Author(s):  
Andrew Clarke
Keyword(s):  
Metabolic Rate ◽  
Resting Metabolic Rate ◽  
Effect Of Temperature ◽  
Thermal Ecology ◽  
Model Data ◽  
Metabolic Theory ◽  
Physical Explanation ◽  
Boltzmann Factor ◽  
Scaling Exponents ◽  
Metabolic Theory Of Ecology

The model of West, Brown & Enquist (WBE) is built on the assumption that the metabolic rate of cells is determined by the architecture of the vascular network that supplies them with oxygen and nutrients. For a fractal-like network, and assuming that evolution has minimised cardiovascular costs, the WBE model predicts that s=metabolism should scale with mass with an exponent, b, of 0.75 at infinite size, and ~ 0.8 at realistic larger sizes. Scaling exponents ~ 0.75 for standard or resting metabolic rate are observed widely, but far from universally, including in some invertebrates with cardiovascular systems very different from that assumed in the WBE model. Data for field metabolic rate in vertebrates typically exhibit b ~ 0.8, which matches the WBE prediction. Addition of a simple Boltzmann factor to capture the effects of body temperature on metabolic rate yields the central equation of the Metabolic Theory of Ecology (MTE). The MTE has become an important strand in ecology, and the WBE model is the most widely accepted physical explanation for the scaling of metabolic rate with body mass. Capturing the effect of temperature through a Boltzmann factor is a useful statistical description but too simple to qualify as a complete physical theory of thermal ecology.

Analysis of Ammonia Volatilization Loss from a Paddy Soil With Empirical and Mechanistic Models

2021 ◽  
pp. 2000230
Author(s):  
Wen‐Ming Xie ◽  
Pei‐Kun Yuan ◽  
You Ma ◽  
Wei‐Ming Shi ◽  
Hai‐Lin Zhang ◽  
...  
Keyword(s):  
Paddy Soil ◽  
Ammonia Volatilization ◽  
Mechanistic Models ◽  
Empirical And Mechanistic Models

Estimation of enteric methane emissions trends (1990–2008) from Manitoba beef cattle using empirical and mechanistic models

2011 ◽  
Vol 91 (2) ◽  
pp. 305-321 ◽  
Author(s):  
Aklilu Alemu ◽  
K. H. Ominski ◽  
E. Kebreab
Keyword(s):  
Beef Cattle ◽  
Methane Emissions ◽  
Mechanistic Models ◽  
Tier 2 ◽  
Cattle Population ◽  
Production Environment ◽  
Feed Composition ◽  
Enteric Methane ◽  
Empirical And Mechanistic Models ◽  
Enteric Methane Emissions

Alemu, A. W., Ominski, K. H. and Kebreab, E. 2011. Estimation of enteric methane emissions trends (1990–2008) from Manitoba beef cattle using empirical and mechanistic models. Can. J. Anim. Sci. 91: 305–321. The objective of this study was to estimate and assess trends in enteric methane (CH4) emissions from the Manitoba beef cattle population from the base year of 1990 to 2008 using mathematical models. Two empirical (statistical) models: Intergovernmental Panel on Climate Change (IPCC) Tier 2 and a nonlinear equation (Ellis), and two dynamic mechanistic models: MOLLY (v3) and COWPOLL were used. Beef cattle in Manitoba were categorized in to 29 distinct subcategories based on management practice, physiological status, gender, age and production environment. Data on animal performance, feeding and management practices and feed composition were collected from the literature as well as from provincial and national sources. Estimates of total enteric CH4 production from the Manitoba beef cattle population varied between 0.9 and 2.4 Mt CO2 eq. from 1990 to 2008. Regardless of the type of models used, average CH4 emissions for 2008 were estimated to be 45.2% higher than 1990 levels. More specifically, CH4 emissions tended to increase between 1990 and 1996. Emissions were relatively stable between 1996 and 2002, increased between 2003 and 2005, but declined by 13.2% between 2005 and 2008, following the same trend as that observed in the beef cattle population. Models varied in their estimates of CH4 conversion rate (Ym, percent gross energy intake), emission factor (kg CH4 head−1 yr−1) and CH4 production. Total CH4 production estimates ranged from 1.2 to 2.0 Mt CO2 eq. for IPCC Tier 2, from 0.9 to 1.5 Mt CO2 eq. for Ellis, from 1.3 to 2.1 Mt CO2 eq. for COWPOLL and from 1.5 to 2.4 Mt CO2 eq. for MOLLY. The results indicate that enteric CH4 estimates and emission trends in Manitoba were influenced by the type of model and beef cattle population. As such, it is necessary to use appropriate models for reliable estimates for enteric CH4 inventory. A more robust approach may be to integrate different models by using mechanistic models to estimate regional Ym values, which may then be used as input for the IPCC Tier 2 model.

Marine copepod diversity patterns and the metabolic theory of ecology

Oecologia ◽  
2010 ◽  
Vol 166 (2) ◽  
pp. 349-355 ◽  
Author(s):  
Isabelle Rombouts ◽  
Grégory Beaugrand ◽  
Frédéric Ibaňez ◽  
Sanae Chiba ◽  
Louis Legendre
Keyword(s):  
Metabolic Theory ◽  
Diversity Patterns ◽  
Metabolic Theory Of Ecology ◽  
Marine Copepod

scholarly journals Flawed evidence supporting the Metabolic Theory of Ecology may undermine goals of ecosystem-based fishery management: the case of invasive Indo-Pacific lionfish in the western Atlantic

2016 ◽  
Vol 74 (5) ◽  
pp. 1256-1267
Author(s):  
Diego Valderrama ◽  
KathrynAnn H. Fields
Keyword(s):  
Fishery Management ◽  
Environmental Temperature ◽  
Growth Parameters ◽  
Fish Mortality ◽  
Natural Mortality ◽  
Metabolic Theory ◽  
Prey Fish ◽  
Western Atlantic ◽  
Fish Stocks ◽  
Metabolic Theory Of Ecology

Given its ability to yield predictions for very diverse phenomena based only on two parameters—body size and temperature—the Metabolic Theory of Ecology (MTE) has earned a prominent place among ecology’s efficient theories. In a seminal article, the leading proponents of the MTE claimed that the theory was supported by evidence from Pauly’s (On the interrelationships between natural mortality, growth parameters, and mean environmental temperature in 175 fish stocks. Journal Du Conseil International Pour L’Exploration de la mer 39:175–192) dataset on natural mortality, biomass, and environmental temperature for 175 fish stocks spanning tropical, temperate, and polar locations. We demonstrate that the evidence presented by the proponents of the MTE is flawed because it fails to account for the fact that Pauly re-estimated environmental temperatures for polar fish as ‘physiologically effective temperatures’ to correct for their ‘abnormally’ high natural (mass-corrected) mortalities, which on average turned out to be similar to (rather than lower than) the mortalities recorded for temperate fish. Failing to account for these modifications skews the coefficients from MTE regression models and wrongly validates predictions from the theory. It is important to point out these deficiencies given the broad appeal of the MTE as a theoretical framework for applied ecological research. In a recent application, the MTE was used to estimate biomass production rates of prey fish in a model of invasive Indo-Pacific lionfish (Pterois volitans and P. miles) predation in Bahamian reefs. We show that the MTE coefficients may lead to a drastic overestimation of prey fish mortality and productivity rates, leading to erroneous estimations of target densities for ecological control of lionfish stocks. A set of robust mortality-weight coefficients is proposed as an alternative to the MTE.

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