Comparative thermal performance ofOrbicella franksiat its latitudinal range limits

AbstractTemperature drives biological responses that scale from the cellular to ecosystem levels and thermal sensitivity will shape organismal functions and population dynamics as the world warms. Reef building corals are sensitive to temperature due to their endosymbiotic relationship with single celled dinoflagellates, with mass mortality events increasing in frequency and magnitude. The purpose of this study was to quantify the thermal sensitivity of important physiological functions of a Caribbean reef-building coral,Orbicella franksithrough the measurement of thermal performance curves (TPCs). We compared TPC metrics (thermal optimum, critical maximum, activation energy, deactivation energy, and rate at a standardized temperature) between two populations at the northern and southern extent of the geographic range of this species. We further compared essential coral organismal processes (gross photosynthesis, respiration, and calcification) within a site to determine which function is most sensitive to thermal stress using a hierarchical Bayesian modeling approach. We found evidence for differences in thermal performance, which could be due to thermal adaptation or acclimatization, with higher TPC metrics (thermal optimum and critical maximum) in warmer Panama, compared to cooler Bermuda. We also documented the hierarchy in thermal sensitivity of essential organismal functions within a population, with respiration less sensitive than photosynthesis, which was less sensitive than calcification. Understanding thermal performance of corals is essential for projecting coral reef futures, given that key biological functions necessary to sustain coral reef ecosystems are thermally-mediated.Summary statementWe apply a thermal performance curve approach to a variety of fitness related parameters in a reef building coral across its geographic range and various functions to improve our understanding of the inherent variability in thermal tolerance.

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Phytoplankton thermal responses adapt in the absence of hard thermodynamic constraints

10.1101/452250 ◽

2018 ◽

Cited By ~ 1

Author(s):

Dimitrios - Georgios Kontopoulos ◽

Erik van Sebille ◽

Michael Lange ◽

Gabriel Yvon-Durocher ◽

Timothy G. Barraclough ◽

...

Keyword(s):

Thermal Performance ◽

Thermal Sensitivity ◽

Meta Analysis ◽

Habitat Type ◽

Performance Curve ◽

Thermal Environments ◽

Thermal Performance Curve ◽

Performance Curves ◽

Minor Influence ◽

A Minor

AbstractTo better predict how populations and communities respond to climatic temperature variation, it is necessary to understand how the shape of the response of fitness-related traits to temperature evolves (the thermal performance curve). Currently, there is disagreement about the extent to which the evolution of thermal performance curves is constrained. One school of thought has argued for the prevalence of thermodynamic constraints through enzyme kinetics, whereas another argues that adaptation can—at least partly—overcome such constraints. To shed further light on this debate, we perform a phylogenetic meta-analysis of the thermal performance curves of growth rate of phytoplankton—a globally important functional group—, controlling for environmental effects (habitat type and thermal regime). We find that thermodynamic constraints have a minor influence on the shape of the curve. In particular, we detect a very weak increase of maximum performance with the temperature at which the curve peaks, suggesting a weak “hotter-is-better” constraint. Also, instead of a constant thermal sensitivity of growth across species, as might be expected from strong constraints, we find that all aspects of the thermal performance curve evolve along the phylogeny. Our results suggest that phytoplankton thermal performance curves adapt to thermal environments largely in the absence of hard thermodynamic constraints.

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Adaptive evolution shapes the present-day distribution of the thermal sensitivity of population growth rate

10.1101/712885 ◽

2019 ◽

Cited By ~ 2

Author(s):

Dimitrios - Georgios Kontopoulos ◽

Thomas P. Smith ◽

Timothy G. Barraclough ◽

Samraat Pawar

Keyword(s):

Climate Change ◽

Growth Rate ◽

Adaptive Evolution ◽

Thermal Performance ◽

Population Growth Rate ◽

Thermal Sensitivity ◽

Rapid Evolution ◽

Performance Curve ◽

Thermal Performance Curve ◽

The Relationship

AbstractDeveloping a thorough understanding of how ectotherm physiology adapts to different thermal environments is of crucial importance, especially in the face of global climate change. A key aspect of an organism’s thermal performance curve—the relationship between fitness-related trait performance and temperature—is its thermal sensitivity, i.e., the rate at which trait values increase with temperature within its typically-experienced thermal range. For a given trait, the distribution of thermal sensitivities across species, often quantified as “activation energy” values, is typically right-skewed. Currently, the mechanisms that generate this distribution are unclear, with considerable debate about the role of thermodynamic constraints vs adaptive evolution. Here, using a phylogenetic comparative approach, we study the evolution of the thermal sensitivity of population growth rate across phytoplankton (Cyanobacteria and eukaryotic microalgae) and prokaryotes (bacteria and archaea), two microbial groups that play a major role in the global carbon cycle. We find that thermal sensitivity across these groups is moderately phylogenetically heritable, and that its distribution is shaped by repeated evolutionary convergence throughout its parameter space. More precisely, we detect bursts of adaptive evolution in thermal sensitivity, increasing the amount of overlap among its distributions in different clades. We obtain qualitatively similar results from evolutionary analyses of the thermal sensitivities of two physiological rates underlying growth rate: net photosynthesis and respiration of plants. Furthermore, we find that these episodes of evolutionary convergence are consistent with two opposing forces: decrease in thermal sensitivity due to environmental fluctuations and increase due to adaptation to stable environments. Overall, our results indicate that adaptation can lead to large and relatively rapid shifts in thermal sensitivity, especially in microbes where rapid evolution can occur at short time scales. Thus, more attention needs to be paid to elucidating the implications of rapid evolution in organismal thermal sensitivity for ecosystem functioning.Author summaryChanges in environmental temperature influence the performance of biological traits (e.g., respiration rate) in ectotherms, with the relationship between trait performance and temperature (the “thermal performance curve”) being single-peaked. Understanding how thermal performance curves adapt to different environments is important for predicting how organisms will be impacted by climate change. One key aspect of the shape of these curves is the thermal sensitivity near temperatures typically experienced by the species. Whether and how thermal sensitivity responds to different environments is a topic of active debate. To shed light on this, here we perform an evolutionary analysis of the thermal sensitivity of three key traits of prokaryotes, phytoplankton, and plants. We show that thermal sensitivity does not evolve in a gradual manner, but can differ considerably even between closely related species. This suggests that thermal sensitivity undergoes rapid adaptive evolution, which is further supported by our finding that thermal sensitivity varies weakly with latitude. We conclude that variation in thermal sensitivity arises partly from adaptation to environmental factors and that this may need to be accounted for in ecophysiological models.

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A resurrection study reveals limited evolution of thermal performance in response to recent climate change across the geographic range of the scarlet monkeyflower

10.1101/2020.02.14.934166 ◽

2020 ◽

Author(s):

Rachel Wooliver ◽

Silas B. Tittes ◽

Seema N. Sheth

Keyword(s):

Climate Change ◽

Thermal Performance ◽

Thermal Adaptation ◽

Leading Edge ◽

Geographic Range ◽

Average Decrease ◽

Climate Anomalies ◽

Trade Offs ◽

Evolutionary Response ◽

Recent Climate

AbstractEvolutionary rescue can prevent populations from declining under climate change, and should be more likely at high-latitude, “leading” edges of species’ ranges due to greater temperature anomalies and gene flow from warm-adapted populations. Using a resurrection study with seeds collected before and after a seven-year period of record warming, we tested for thermal adaptation in the scarlet monkeyflower Mimulus cardinalis. We grew ancestors and descendants from northern-edge, central, and southern-edge populations across eight temperatures. Despite recent climate anomalies, populations showed limited evolution of thermal performance curves. However, one southern population evolved a narrower thermal performance breadth by 1.25 °C, which matches the direction and magnitude of the average decrease in seasonality experienced. Consistent with the climate variability hypothesis, thermal performance breadth increased with temperature seasonality across the species’ geographic range. Inconsistent with performance trade-offs between low and high temperatures across populations, we did not detect a positive relationship between thermal optimum and mean temperature. These findings fail to support the hypothesis that evolutionary response to climate change is greatest at the leading edge, and suggest that the evolution of thermal performance is unlikely to rescue most populations from the detrimental effects of rapidly changing climate.

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Nutrient and sediment loading affect multiple facets of functionality in a tropical branching coral

Journal of Experimental Biology ◽

10.1242/jeb.225045 ◽

2020 ◽

Vol 223 (21) ◽

pp. jeb225045

Author(s):

Danielle M. Becker ◽

Nyssa J. Silbiger

Keyword(s):

Coral Reef ◽

Nitrogen Content ◽

Thermal Performance ◽

Nutrient Loading ◽

Metabolic Responses ◽

Coral Host ◽

Percent Cover ◽

Sediment Loading ◽

Anthropogenic Stressors ◽

Coral Reef Ecosystems

ABSTRACTCoral reefs, one of the most diverse ecosystems in the world, face increasing pressures from global and local anthropogenic stressors. Therefore, a better understanding of the ecological ramifications of warming and land-based inputs (e.g. sedimentation and nutrient loading) on coral reef ecosystems is necessary. In this study, we measured how a natural nutrient and sedimentation gradient affected multiple facets of coral functionality, including endosymbiont and coral host response variables, holobiont metabolic responses and percent cover of Pocillopora acuta colonies in Mo′orea, French Polynesia. We used thermal performance curves to quantify the relationship between metabolic rates and temperature along the environmental gradient. We found that algal endosymbiont percent nitrogen content, endosymbiont densities and total chlorophyll a content increased with nutrient input, while endosymbiont nitrogen content per cell decreased, likely representing competition among the algal endosymbionts. Nutrient and sediment loading decreased coral metabolic responses to thermal stress in terms of their thermal performance and metabolic rate processes. The acute thermal optimum for dark respiration decreased, along with the maximal performance for gross photosynthetic and calcification rates. Gross photosynthetic and calcification rates normalized to a reference temperature (26.8°C) decreased along the gradient. Lastly, percent cover of P. acuta colonies decreased by nearly two orders of magnitude along the nutrient gradient. These findings illustrate that nutrient and sediment loading affect multiple levels of coral functionality. Understanding how local-scale anthropogenic stressors influence the responses of corals to temperature can inform coral reef management, particularly in relation to the mediation of land-based inputs into coastal coral reef ecosystems.

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Turbid Coral Reefs: Past, Present and Future—A Review

Diversity ◽

10.3390/d13060251 ◽

2021 ◽

Vol 13 (6) ◽

pp. 251

Author(s):

Adi Zweifler (Zvifler) ◽

Michael O’Leary ◽

Kyle Morgan ◽

Nicola K. Browne

Keyword(s):

Climate Change ◽

Coral Reef ◽

Coral Reefs ◽

Environmental Change ◽

Scientific Literature ◽

Conservation Status ◽

Climate Change Impacts ◽

Geographic Range ◽

Reef Complex ◽

Sediment Input

Increasing evidence suggests that coral reefs exposed to elevated turbidity may be more resilient to climate change impacts and serve as an important conservation hotspot. However, logistical difficulties in studying turbid environments have led to poor representation of these reef types within the scientific literature, with studies using different methods and definitions to characterize turbid reefs. Here we review the geological origins and growth histories of turbid reefs from the Holocene (past), their current ecological and environmental states (present), and their potential responses and resilience to increasing local and global pressures (future). We classify turbid reefs using new descriptors based on their turbidity regime (persistent, fluctuating, transitional) and sources of sediment input (natural versus anthropogenic). Further, by comparing the composition, function and resilience of two of the most studied turbid reefs, Paluma Shoals Reef Complex, Australia (natural turbidity) and Singapore reefs (anthropogenic turbidity), we found them to be two distinct types of turbid reefs with different conservation status. As the geographic range of turbid reefs is expected to increase due to local and global stressors, improving our understanding of their responses to environmental change will be central to global coral reef conservation efforts.

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PAK1 phosphorylation of MEK1 regulates fibronectin-stimulated MAPK activation

The Journal of Cell Biology ◽

10.1083/jcb.200212141 ◽

2003 ◽

Vol 162 (2) ◽

pp. 281-291 ◽

Cited By ~ 166

Author(s):

Jill K. Slack-Davis ◽

Scott T. Eblen ◽

Maja Zecevic ◽

Scott A. Boerner ◽

Adel Tarcsafalvi ◽

...

Keyword(s):

Growth Factor ◽

Signal Transduction Pathway ◽

Mapk Signaling ◽

Growth Factor Signaling ◽

Transduction Pathway ◽

Mapk Activation ◽

Src Signaling ◽

Biological Responses ◽

P21 Activated Kinase ◽

A Site

Activation of the Ras–MAPK signal transduction pathway is necessary for biological responses both to growth factors and ECM. Here, we provide evidence that phosphorylation of S298 of MAPK kinase 1 (MEK1) by p21-activated kinase (PAK) is a site of convergence for integrin and growth factor signaling. We find that adhesion to fibronectin induces PAK1-dependent phosphorylation of MEK1 on S298 and that this phosphorylation is necessary for efficient activation of MEK1 and subsequent MAPK activation. The rapid and efficient activation of MEK and phosphorylation on S298 induced by cell adhesion to fibronectin is influenced by FAK and Src signaling and is paralleled by localization of phospho-S298 MEK1 and phospho-MAPK staining in peripheral membrane–proximal adhesion structures. We propose that FAK/Src-dependent, PAK1-mediated phosphorylation of MEK1 on S298 is central to the organization and localization of active Raf–MEK1–MAPK signaling complexes, and that formation of such complexes contributes to the adhesion dependence of growth factor signaling to MAPK.

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