scholarly journals A temperature dependent trophic cascade modifies temperature dependence of ecosystem function

2017 ◽  
Author(s):  
Jessica Garzke ◽  
Stephanie J. Connor ◽  
Ulrich Sommer ◽  
Mary I. O’Connor
Keyword(s):  
Community Structure ◽  
Temperature Dependence ◽  
Ecosystem Function ◽  
Trophic Cascade ◽  
Thermal Gradient ◽  
Phytoplankton Biomass ◽  
Oxygen Flux ◽  
Ecosystem Functions ◽  
Temperature Dependent ◽  
Effects Of Temperature

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

scholarly journals Brain size varies with temperature in vertebrates

2014 ◽  
Author(s):  
James F Gillooly
Keyword(s):  
Body Size ◽  
Body Temperature ◽  
Metabolic Rate ◽  
Temperature Dependence ◽  
Aerobic Capacity ◽  
Brain Size ◽  
Metabolic Rates ◽  
Temperature Dependent ◽  
Spatial And Temporal Scales ◽  
Effects Of Temperature

The tremendous variation in brain size among vertebrates has long been thought to be related to differences in species’ metabolic rates. Species with higher metabolic rates can supply more energy to support the relatively high cost of brain tissue. And yet, while body temperature is known to be a major determinant of metabolic rate, the possible effects of temperature on brain size have scarcely been explored. Thus, here I explore the effects of temperature on brain size among diverse vertebrates (fishes,amphibians, reptiles, birds and mammals). I find that, after controlling for body size,brain size increases exponentially with temperature in much the same way asmetabolic rate. These results suggest that temperature-dependent changes in aerobic capacity, which have long been known to affect physical performance, similarly affect brain size. The observed temperature-dependence of brain size may explain observed gradients in brain size among both ectotherms and endotherms across broad spatial and temporal scales.

Viewing soil systems from the top-down can make microbial ecology predictive for ecosystem functions

2020 ◽  
Author(s):  
Johannes Rousk ◽  
Lettice Hicks
Keyword(s):  
Community Structure ◽  
Microbial Community ◽  
Microbial Communities ◽  
Functional Response ◽  
Community Composition ◽  
Ecosystem Function ◽  
Response Curve ◽  
Ecosystem Processes ◽  
Ecosystem Functions ◽  
Top Down

<p>Understanding the role of ecological communities in maintaining multiple ecosystem processes is a central challenge in ecology. Soil microbial communities perform vital ecosystem functions, such as the decomposition of organic matter to provide plant nutrition. However, despite the functional importance of soil microorganisms, attribution of ecosystem function to particular constituents of the microbial community has been impeded by a lack of information linking microbial processes to community structure.</p><p>Here, we propose a new conceptual framework to determine how microbial communities influence ecosystem processes, by applying a “top-down” approach. Looking from the “top”, we first view the microbial community associated with a specific function as a whole, and describe the dependence of microbial community processes on environmental factors (e.g. the intrinsic temperature dependence of bacterial growth rates), allowing us to define the aggregate functional response curve of the community. We then demonstrate that the whole community contribution to ecosystem function can be predicted, by parameterising the functional response curve with current environmental conditions. In a final step, we show how this functional information can be linked to the taxonomic community composition (amplicon assessments of microbial community composition) in order to identify “biomarker” taxa that capture microbial communities’ regulation of ecosystem processes and the susceptibility of microbial community structure and function to environmental change. Ultimately, these biomarkers may be used as a diagnostic tool, enabling predictions of ecosystem function from community composition information combined with environmental metadata.</p>

scholarly journals Brain size varies with temperature in vertebrates

2014 ◽  
Author(s):  
James F Gillooly
Keyword(s):  
Body Size ◽  
Body Temperature ◽  
Metabolic Rate ◽  
Temperature Dependence ◽  
Aerobic Capacity ◽  
Brain Size ◽  
Metabolic Rates ◽  
Temperature Dependent ◽  
Spatial And Temporal Scales ◽  
Effects Of Temperature

The tremendous variation in brain size among vertebrates has long been thought to be related to differences in species’ metabolic rates. Species with higher metabolic rates can supply more energy to support the relatively high cost of brain tissue. And yet, while body temperature is known to be a major determinant of metabolic rate, the possible effects of temperature on brain size have scarcely been explored. Thus, here I explore the effects of temperature on brain size among diverse vertebrates (fishes,amphibians, reptiles, birds and mammals). I find that, after controlling for body size,brain size increases exponentially with temperature in much the same way asmetabolic rate. These results suggest that temperature-dependent changes in aerobic capacity, which have long been known to affect physical performance, similarly affect brain size. The observed temperature-dependence of brain size may explain observed gradients in brain size among both ectotherms and endotherms across broad spatial and temporal scales.

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 ◽  
...  
Keyword(s):  
Temperature Dependence ◽  
Thermal Gradient ◽  
Gross Primary Production ◽  
Thermal Adaptation ◽  
Functional Trait ◽  
Evolutionary Mechanisms ◽  
Photosynthetic Physiology ◽  
Ecosystem Level ◽  
Effects Of Temperature

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.

scholarly journals Hotter is Smarter: The temperature-dependence of brain size in vertebrates

2013 ◽  
Author(s):  
James JF Gillooly
Keyword(s):  
Body Size ◽  
Body Temperature ◽  
Metabolic Rate ◽  
Temperature Dependence ◽  
Brain Tissue ◽  
Brain Size ◽  
Metabolic Rates ◽  
Temperature Dependent ◽  
Spatial And Temporal Scales ◽  
Effects Of Temperature

The tremendous variation in brain size among vertebrates has long been thought to be related to differences in species’ metabolic rates. Species with higher metabolic rates can supply more energy to support the relatively high cost of brain tissue. And yet, while body temperature is known to be a major determinant of metabolic rate, the possible effects of temperature on brain size have scarcely been explored. Thus, here I explore the effects of temperature on brain size among diverse vertebrates (fishes,amphibians, reptiles, birds and mammals). I find that, after controlling for body size,brain size increases exponentially with temperature in much the same way asmetabolic rate. These results suggest that temperature-dependent changes inaerobic capacity, which have long been known to affect physical performance, similarly affect brain size. The observed temperature-dependence of brain size may explain observed gradients in brain size among both ectotherms and endotherms across broad spatial and temporal scales.

Effects of temperature dependent chemical potential on the Seebeck coefficient of TiS2 thermoelectric material

2011 ◽  
Vol 1314 ◽  
Author(s):  
Tsunehiro Takeuchi ◽  
Akio Yamamoto ◽  
Koto Ogawa
Keyword(s):  
High Resolution ◽  
Seebeck Coefficient ◽  
Temperature Dependence ◽  
Thermoelectric Material ◽  
Chemical Potential ◽  
Photoemission Spectroscopy ◽  
Temperature Dependent ◽  
Angle Resolved Photoemission Spectroscopy ◽  
Guiding Principle ◽  
Effects Of Temperature

ABSTRACTThe relation between chemical potential and Seebeck coefficient was investigated by using high-resolution angle resolved photoemission spectroscopy. The temperature dependence of chemical potential was experimentally determined for the n-type TiS2 thermoelectric material and compared with the measured Seebeck coefficient. We found that the temperature dependence of chemical potential of TiS2 is significantly large, and its effect on Seebeck coefficient is not negligible. This fact strongly indicates that the temperature dependence of chemical potential has to be properly understood to construct the guiding principle for developing new, practical thermoelectric materials.

scholarly journals The temperature dependence of the adrenergic Na+/H+ exchanger of trout erythrocytes

1990 ◽  
Vol 148 (1) ◽  
pp. 303-312 ◽  
Author(s):  
A. R. Cossins ◽  
R. V. Kilbey
Keyword(s):  
Steady State ◽  
Rainbow Trout ◽  
Temperature Dependence ◽  
Effect Of Temperature ◽  
Transport Mechanisms ◽  
Adrenergic Stimulation ◽  
Temperature Dependent ◽  
Effects Of Temperature ◽  
Time Required

The effects of temperature upon the adrenergic Na+/H+ exchange of rainbow trout erythrocytes have been studied in vitro. The initial rates of H+ ejection and of increase of intracellular Na+ [(Na+]i) in adrenergically stimulated cells were highly temperature-dependent, with apparent Arrhenius activation energies of 112.8 +/− 10.0 (mean +/− S.D., N = 4) and 84.1 +/− 3.0 kJ mol-1 (N = 3), respectively. The steady-state [Na+]i following stimulation decreased progressively with cooling, whilst the time required for [Na+]i to return to control values after removal of agonist was greatly increased. The change in intracellular pH resulting from adrenergic stimulation was reduced by cooling, such that at 4 degrees C adrenergic responses were barely measurable. The effect of temperature upon the steady-state [Na+]i and pHi was probably caused by a disparity in the temperature dependence of the transport mechanisms that contribute to the respective steady states.

scholarly journals Consistent Effects of Pesticides on Community Structure and Ecosystem Function in Freshwater Systems

2020 ◽  
Author(s):  
Samantha L. Rumschlag ◽  
Michael B. Mahon ◽  
Jason T. Hoverman ◽  
Thomas R. Raffel ◽  
Hunter J. Carrick ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Community Structure ◽  
Community Composition ◽  
Ecosystem Function ◽  
Ecosystem Functions ◽  
Ecosystem Responses ◽  
Freshwater Systems ◽  
Composition Effects ◽  
Chemical Groups ◽  
Sheer Number

AbstractPredicting ecological effects of contaminants remains challenging because of the sheer number of chemicals and their ambiguous role in biodiversity-ecosystem function relationships. We evaluated responses of pond ecosystems to standardized concentrations of 12 pesticides, nested in four pesticide classes and two pesticide types. We show consistent effects of herbicides and insecticides on ecosystem function, but slightly less consistent effects on community composition. Effects of pesticides on ecosystem functions were often mediated by changes to biodiversity, and our analyses show that consistency in effects of pesticide types on functions was driven by functional redundancy among species. These results suggest that risk assessment of the thousands of registered chemicals on ecosystem responses could be simplified to a smaller number of chemical groups and to groups of functionally redundant taxa.

scholarly journals Shakedown Behaviour of Composite Cylinders With Cross Hole

2010 ◽  
Author(s):  
Haofeng Chen ◽  
Weihang Chen ◽  
Tianbai Li ◽  
James Ure
Keyword(s):  
Thermal Gradient ◽  
Composite Cylinder ◽  
Plastic Limit ◽  
Temperature Dependent ◽  
Matching Method ◽  
Numerical Examples ◽  
Effects Of Temperature ◽  
Shakedown Limit ◽  
Composite Cylinders ◽  
Linear Matching Method

In this study, both the lower and upper bound shakedown limits of a closed-end composite cylinder with or without a cross hole subject to constant internal pressure and a cyclic thermal gradient are calculated by the Linear Matching Method (LMM). Convergence for upper and lower bound shakedown limit of the composite cylinders is sought and shakedown limit interaction diagrams of the numerical examples identifying the regions of reverse plastic limit and ratchet limit are presented. The effects of temperature-dependent yield stress, materials discontinuities, composite cylinder thickness and the existence of cross hole on the shakedown limits are discussed for different geometry parameters. Finally, a safety shakedown envelope is created by formulating the shakedown limit results of different composite material and cylinder thickness ratios with different cross hole sizes.

Dominance determines fish community biomass in a temperate seagrass ecosystem

2019 ◽  
Author(s):  
Aaron Matthius Eger ◽  
Rebecca J. Best ◽  
Julia Kathleen Baum
Keyword(s):  
Species Richness ◽  
Ecosystem Function ◽  
Fish Community ◽  
Prey Capture ◽  
Fish Communities ◽  
Functional Trait ◽  
Ecosystem Functions ◽  
Community Biomass ◽  
Ecosystem Valuation ◽  
Species Abundances

Biodiversity and ecosystem function are often correlated, but there are multiple hypotheses about the mechanisms underlying this relationship. Ecosystem functions such as primary or secondary production may be maximized by species richness, evenness in species abundances, or the presence or dominance of species with certain traits. Here, we combined surveys of natural fish communities (conducted in July and August, 2016) with morphological trait data to examine relationships between diversity and ecosystem function (quantified as fish community biomass) across 14 subtidal eelgrass meadows in the Northeast Pacific (54° N 130° W). We employed both taxonomic and functional trait measures of diversity to investigate if ecosystem function is driven by species diversity (complementarity hypothesis) or by the presence or dominance of species with particular trait values (selection or dominance hypotheses). After controlling for environmental variation, we found that fish community biomass is maximized when taxonomic richness and functional evenness is low, and in communities dominated by species with particular trait values – those associated with benthic habitats and prey capture. While previous work on fish communities has found that species richness is positively correlated with ecosystem function, our results instead highlight the capacity for regionally prevalent and locally dominant species to drive ecosystem function in moderately diverse communities. We discuss these alternate links between community composition and ecosystem function and consider their divergent implications for ecosystem valuation and conservation prioritization.

Sign in / Sign up

Export Citation Format

Share Document