scholarly journals Thermal adaptation constrains the temperature dependence of ecosystem metabolism

2017 ◽  
Author(s):  
Daniel Padfield ◽  
Chris Lowe ◽  
Angus Buckling ◽  
Richard Ffrench-Constant ◽  
Elisa Schaum ◽  
...  

ABSTRACTGross primary production (GPP) is the largest flux in the carbon cycle, yet its response to global warming is highly uncertain. The temperature sensitivity of GPP is directly linked to photosynthetic physiology, but the response of GPP to warming over longer timescales could also be shaped by ecological and evolutionary processes that drive variation community structure and functional trait distributions. Here, we show that selection on photosynthetic traits within and across taxa dampen the effects of temperature on GPP across a catchment of geothermally heated streams. Autotrophs from cold streams had higher photosynthetic rates and after accounting for differences in biomass among sites, rates of ecosystem-level GPP were independent of temperature, despite a 20 ºC thermal gradient. Our results suggest that thermal adaptation constrains the long-term temperature dependence of GPP, and highlights the importance of considering physiological, ecological and evolutionary mechanisms when predicting how ecosystem-level processes respond to warming.


2017 ◽  
Author(s):  
Jessica Garzke ◽  
Stephanie J. Connor ◽  
Ulrich Sommer ◽  
Mary I. O’Connor

AbstractEcological communities and their ecosystem functions are sensitive to temperature, and aquatic habitats worldwide continue to experience unprecedented warming. Understanding ecological effects of warming requires linking empirical evidence to theories that allow projection to unobserved conditions. Metabolic scaling theory and its tests suggest that warming accelerates ecosystem functions (e.g., oxygen flux), yet this prediction apparently contradicts community-level studies suggesting warming is a stressor that can reduce ecosystem function. We sought to reconcile these predictions with an experimental test of the hypothesis that cascading trophic interactions modify the temperature-dependence of community structure and ecosystem fluxes. In a series of independent freshwater ecosystems exposed to a thermal gradient, we found that warmer temperatures strengthened the trophic cascade increased and indirectly changed community structure by altering grazer species composition and phytoplankton biomass. Temperature-driven community shifts only modestly affected the temperature dependence of net ecosystem oxygen fluxes. Over the 10 °C thermal gradient, NPP and ER increased ∼2.7-fold among ecosystems, while standing phytoplankton biomass declined by 85-95%. The exponential increase in oxygen flux over the thermal gradient, as well as monotonic declines in phytoplankton standing stock, suggested no threshold effects of warming across systems. We also observed temperature variation over time, within ecosystems. For phytoplankton biomass, temporal variation had the opposite effect to spatial variation, suggesting that within-community temporal change in community structure was not predicted by space-for-time substitution. We conclude that food chain length can modify effects of temperature on ecosystem fluxes, but that temperature can still have continuous and positive effects on ecosystem fluxes, consistent with patterns based on large-scale, macroecological comparisons. Changes in community structure, including temperature dependent trophic cascades, may be compatible with prevailing and predictable effects of temperature on ecosystem functions related to fundamental effects of temperature on metabolism.Statement of authorshipJG & MIO designed the study, MIO & US provided materials, JG & SJC performed research and collected data, JG performed zooplankton analysis, SJC performed phytoplankton analysis, JG & MIO performed modeling work, analyzed data output, and wrote the first draft, and all authors contributed substantially to reviews



2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Hongjun Wang ◽  
Jianqing Tian ◽  
Huai Chen ◽  
Mengchi Ho ◽  
Rytas Vilgalys ◽  
...  

AbstractPeatlands have persisted as massive carbon sinks over millennia, even during past periods of climate change. The commonly accepted theory of abiotic controls (mainly anoxia and low temperature) over carbon decomposition cannot fully explain how vast low-latitude shrub/tree dominated (wooded) peatlands consistently accrete peat under warm and seasonally unsaturated conditions. Here we show, by comparing the composition and ecological traits of microbes between Sphagnum- and shrub-dominated peatlands, that slow-growing microbes decisively dominate the studied shrub-dominated peatlands, concomitant with plant-induced increases in highly recalcitrant carbon and phenolics. The slow-growing microbes metabolize organic matter thirty times slower than the fast-growing microbes that dominate our Sphagnum-dominated site. We suggest that the high-phenolic shrub/tree induced shifts in microbial composition may compensate for positive effects of temperature and/or drought on metabolism over time in peatlands. This biotic self-sustaining process that modulates abiotic controls on carbon cycling may improve projections of long-term, climate-carbon feedbacks in peatlands.





2021 ◽  
Author(s):  
Michael P. Cartwright ◽  
Jeremy J. Harrison ◽  
David P. Moore

<p>Carbonyl sulfide (OCS) is the most abundant sulfur containing gas in the atmosphere and is an important source of stratospheric aerosol. Furthermore, it has been shown that OCS can be used as a proxy for photosynthesis, which is a powerful tool in quantifying global gross primary production. While considerable improvements have been made in our understanding of the location and magnitude of OCS fluxes over the past few decades, recent studies highlight the need for a new satellite dataset to help reduce the uncertainties in current estimations. The Infrared Atmospheric Sounding Interferometer (IASI) instruments on-board the MetOp satellites offer over 14 years of nadir viewing radiance measurements with excellent spatial coverage. Given that there are currently three IASI instruments in operation, there is the potential for a significantly larger OCS dataset than is currently available elsewhere. Retrievals of OCS from these IASI radiances have been made using an adapted version of the University of Leicester IASI Retrieval Scheme (ULIRS). OCS total column amounts are calculated from profiles retrieved on a 31-layer equidistant pressure grid, using an optimal estimation approach for microwindows in the range 2000 – 2100 cm<sup>-1</sup> wavenumbers. Sensitivity of the measurements peak in the mid-troposphere, between 5 – 10 km.</p><p>The outlook of this work is to produce a long-term OCS satellite observational data set that provides fresh insight to the spatial distribution and trend of atmospheric OCS. Here, we present subsets of data in the form of case studies for different geographic regions and time periods.</p>



2002 ◽  
Vol 11 (3) ◽  
pp. 88-93 ◽  
Author(s):  
Lynn Carol Miller ◽  
Anila Putcha-Bhagavatula ◽  
William C. Pedersen

Have men and women evolved sex-distinct mating preferences for short-term and long-term mating, as postulated by some evolutionary theorists? Direct tests of assumptions, consideration of confounds with gender, and examination of the same variables for both sexes suggest men and women are remarkably similar. Furthermore, cross-species comparisons indicate that humans do not evidence mating mechanisms indicative of short-term mating (e.g., large female sexual skins, large testicles). Understanding human variability in mating preferences is apt to involve more detailed knowledge of the links between these preferences and biological and chemical mechanisms associated with sexual motivation, sexual arousal, and sexual functioning.



2014 ◽  
Vol 11 (16) ◽  
pp. 4529-4540 ◽  
Author(s):  
L. S. García-Corral ◽  
E. Barber ◽  
A. Regaudie-de-Gioux ◽  
S. Sal ◽  
J. M. Holding ◽  
...  

Abstract. The temperature dependence of planktonic metabolism in the subtropical North Atlantic Ocean was assessed on the basis of measurements of gross primary production (GPP), community respiration (CR) and net community production (NCP), as well as experimental assessments of the response of CR to temperature manipulations. Metabolic rates were measured at 68 stations along three consecutive longitudinal transects completed during the Malaspina 2010 Expedition, in three different seasons. Temperature gradients were observed in depth and at basin and seasonal scale. The results showed seasonal variability in the metabolic rates, the highest rates being observed during the spring transect. The overall mean integrated GPP / CR ratio was 1.39 ± 0.27 decreasing from winter to summer, and the NCP for the subtropical North Atlantic Ocean during the cruises exhibits net autotrophy (NCP > 0) in about two-thirds (66%) of the total sampled communities. Also, we reported the activation energies describing the temperature dependence of planktonic community metabolism, which was generally higher for CR than for GPP in the subtropical North Atlantic Ocean, as the metabolic theory of ecology predicts. Furthermore, we made a comparison of activation energies describing the responses to in situ temperature in the field (EaCR = 1.64 ± 0.36 eV) and those derived experimentally by temperature manipulations (EaCR = 1.45 ± 0.6 eV), which showed great consistency.



2016 ◽  
Author(s):  
Paul K. Abram ◽  
Guy Boivin ◽  
Joffrey Moiroux ◽  
Jacques Brodeur

AbstractTemperature imposes significant constraints on ectothermic animals, and these organisms have evolved numerous adaptations to respond to these constraints. While the impacts of temperature on the physiology of ectotherms have been extensively studied, there are currently no frameworks available that outline the multiple and often simultaneous pathways by which temperature can affect behaviour. Drawing from the literature on insects, we propose a unified framework that should apply to all ectothermic animals, generalizing temperature's behavioural effects into (1) Kinetic effects, resulting from temperature's bottom-up constraining influence on metabolism and neurophysiology over a range of timescales (from short-to long-term), and (2) Integrated effects, where the top-down integration of thermal information intentionally initiates or modifies a behaviour (behavioural thermoregulation, thermal orientation, thermosensory behavioural adjustments). We discuss the difficulty in distinguishing adaptive behavioural changes due to temperature from behavioural changes that are the products of constraints, and propose two complementary approaches to help make this distinction and class behaviours according to our framework: (i) behavioural kinetic null modeling and (ii) behavioural ecology experiments using temperature-insensitive mutants. Our framework should help to guide future research on the complex relationship between temperature and behaviour in ectothermic animals.



2020 ◽  
pp. 134-141
Author(s):  
S. B. Moiseev

The factors influencing the possibility of the theory of key competencies adaptation within the traditional ideas of the resource approach to ensure the long-term competitiveness of companies have been considered. For this purpose, the review of features of application of key competencies during the formation of strategies of the industrial companies of mature sectors of industries has been carried out, in which thanks to action of evolutionary mechanisms of technological and organizational development there are objective preconditions for creation of steady competitive advantages on their basis. The necessity of development of methodological approaches to the formation of company’s competitive strategy in the sector of electrical production based on the formation of organizational-economic mechanism of adaptation to external influences and internal changes to manage the development of key competencies as factors of sustainable competitive advantage in the future and the formation of long-term effective business development model of the enterprise, has been substantiated.



2021 ◽  
Vol 288 (1953) ◽  
pp. 20210428
Author(s):  
Staffan Jacob ◽  
Delphine Legrand

Intra- and interspecific variability can both ensure ecosystem functions. Generalizing the effects of individual and species assemblages requires understanding how much within and between species trait variation is genetically based or results from phenotypic plasticity. Phenotypic plasticity can indeed lead to rapid and important changes of trait distributions, and in turn community functionality, depending on environmental conditions, which raises a crucial question: could phenotypic plasticity modify the relative importance of intra- and interspecific variability along environmental gradients? We quantified the fundamental niche of five genotypes in monocultures for each of five ciliate species along a wide thermal gradient in standardized conditions to assess the importance of phenotypic plasticity for the level of intraspecific variability compared to differences between species. We showed that phenotypic plasticity strongly influences trait variability and reverses the relative extent of intra- and interspecific variability along the thermal gradient. Our results show that phenotypic plasticity may lead to either increase or decrease of functional trait variability along environmental gradients, making intra- and interspecific variability highly dynamic components of ecological systems.



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