scholarly journals Foraminiferal holobiont thermal tolerance under future warming – roommate problems or successful collaboration?

2020 ◽  
Vol 17 (8) ◽  
pp. 2341-2348 ◽  
Author(s):  
Doron Pinko ◽  
Sigal Abramovich ◽  
Danna Titelboim
Keyword(s):  
Thermal Tolerance ◽  
Net Photosynthesis ◽  
Loss Of Life ◽  
Relative Contribution ◽  
Large Benthic Foraminifera ◽  
Algal Symbionts ◽  
Progressive Loss ◽  
Future Warming ◽  
Roommate Problems ◽  
Successful Collaboration

Abstract. Understanding the response of marine organisms to expected future warming is essential. Large benthic foraminifera (LBF) are symbiont-bearing protists considered to be major carbonate producers and ecosystem engineers. We examined the thermal tolerance of two main types of LBF holobionts characterized by different algal symbionts and shell types (resulting from alternative biomineralization mechanisms): the hyaline diatom-bearing Amphistegina lobifera and the porcellaneous-dinoflagellate-bearing Sorites orbiculus. In order to assess the holobiont thermal tolerance we separately evaluated foraminiferal calcification rates and symbionts' net photosynthesis under present-day and future warming scenarios. Our results show that both holobionts exhibit progressive loss-of-life functions between 32 and 35 ∘C. This sensitivity differs in the magnitude of their response: calcification of A. lobifera was drastically reduced compared with S. orbiculus. Thus, future warming may significantly shift the relative contribution of the two species as carbonate producers. Moreover, A. lobifera exhibited a synchronous response of calcification and net photosynthesis. In contrast, in S. orbiculus the symbionts decreased net photosynthesis prior to calcification. This implies that algal symbionts limit the resilience of the halobiont.

scholarly journals Foraminiferal holobiont thermal tolerance under climate change – Roommates problems or successful collaboration?

2020 ◽  
Author(s):  
Doron Pinko ◽  
Sigal Abramovich ◽  
Danna Titelboim
Keyword(s):  
Climate Change ◽  
Thermal Tolerance ◽  
Photosynthetic Activity ◽  
Extreme Temperature ◽  
Relative Contribution ◽  
Large Benthic Foraminifera ◽  
Algal Symbionts ◽  
Future Warming ◽  
Successful Collaboration

Abstract. Understanding the response of marine organisms to expected future warming is essential. Large Benthic Foraminifera (LBF) are symbiont bearing protists considered to be major carbonate producers and ecosystems engineers. We examined the thermal tolerance of two main types of LBF holobionts characterized by different algal symbionts and shell types (resulted from alternative biomineralization mechanisms): The hyaline diatom bearing, Amphistegina lobifera, and the porcelaneous dinoflagellate bearing, Sorites orbiculus. To assess the relative contribution of host and symbiont algae to the holobiont thermal tolerance we separately evaluated their response by measuring calcification rates and photosynthetic activity under present-day and future warming scenarios. Our results show that both holobionts exhibit thermal resilience up to 32 °C and sensitivity to 35 °C. This sensitivity differs in the magnitude of their response: calcification of A. lobifera was completely inhibited while it was only reduced in S. orbiculus. Thus, future warming will significantly shift the relative contribution of the two species as carbonate producers. Moreover, A. lobifera exhibited a synchronized response of the host and symbionts. In contrast, in S. orbiculus the symbionts responded prior to the host, possibly limiting its resilience. Our results also demonstrate the role of pre-exposure and acclimation processes of host, symbionts or both in mitigating future warming. It highlights the possibility that while pre-exposure to moderate temperatures benefits the holobiont, in cases of extreme temperature it might reduce its thermal tolerance.

scholarly journals Adaptation to a latitudinal thermal gradient within a widespread copepod species: the contributions of genetic divergence and phenotypic plasticity

2017 ◽  
Vol 284 (1853) ◽  
pp. 20170236 ◽  
Author(s):  
Ricardo J. Pereira ◽  
Matthew C. Sasaki ◽  
Ronald S. Burton
Keyword(s):  
Phenotypic Plasticity ◽  
Genetic Divergence ◽  
Thermal Tolerance ◽  
Large Scale ◽  
Thermal Adaptation ◽  
Common Garden ◽  
Latitudinal Gradients ◽  
Physiological Limits ◽  
Relative Contribution ◽  
Common Garden Experiments

Understanding how populations adapt to heterogeneous thermal regimes is essential for comprehending how latitudinal gradients in species diversification are formed, and how taxa will respond to ongoing climate change. Adaptation can occur by innate genetic factors, by phenotypic plasticity, or by a combination of both mechanisms. Yet, the relative contribution of such mechanisms to large-scale latitudinal gradients of thermal tolerance across conspecific populations remains unclear. We examine thermal performance in 11 populations of the intertidal copepod Tigriopus californicus , ranging from Baja California Sur (Mexico) to British Columbia (Canada). Common garden experiments show that survivorship to acute heat-stress differs between populations (by up to 3.8°C in LD 50 values), reflecting a strong genetic thermal adaptation. Using a split-brood experiment with two rearing temperatures, we also show that developmental phenotypic plasticity is beneficial to thermal tolerance (by up to 1.3°C), and that this effect differs across populations. Although genetic divergence in heat tolerance strongly correlates with latitude and temperature, differences in the plastic response do not. In the context of climate warming, our results confirm the general prediction that low-latitude populations are most susceptible to local extinction because genetic adaptation has placed physiological limits closer to current environmental maxima, but our results also contradict the prediction that phenotypic plasticity is constrained at lower latitudes.

scholarly journals Thermal tolerance, acclimatory capacity and vulnerability to global climate change

2007 ◽  
Vol 4 (1) ◽  
pp. 99-102 ◽  
Author(s):  
Piero Calosi ◽  
David T Bilton ◽  
John I Spicer
Keyword(s):  
Climate Change ◽  
At Risk ◽  
Thermal Tolerance ◽  
Global Climate ◽  
Marine Animals ◽  
Vulnerability To Climate Change ◽  
Diving Beetles ◽  
Mountain Systems ◽  
Future Warming ◽  
Upper Thermal Tolerance

Despite evidence that organismal distributions are shifting in response to recent climatic warming, we have little information on direct links between species' physiology and vulnerability to climate change. We demonstrate a positive relationship between upper thermal tolerance and its acclimatory ability in a well-defined clade of closely related European diving beetles. We predict that species with the lowest tolerance to high temperatures will be most at risk from the adverse effects of future warming, since they have both low absolute thermal tolerance and poor acclimatory ability. Upper thermal tolerance is also positively related to species' geographical range size, meaning that species most at risk are already the most geographically restricted ones, being endemic to Mediterranean mountain systems. Our findings on the relationship between tolerance and acclimatory ability contrast with results from marine animals, suggesting that generalizations regarding thermal tolerance and responses to future rapid climate change may be premature.

scholarly journals Trophic strategy and bleaching resistance in reef-building corals

2020 ◽  
Vol 6 (15) ◽  
pp. eaaz5443 ◽  
Author(s):  
Inga E. Conti-Jerpe ◽  
Philip D. Thompson ◽  
Cheong Wai Martin Wong ◽  
Nara L. Oliveira ◽  
Nicolas N. Duprey ◽  
...  
Keyword(s):  
Thermal Tolerance ◽  
Niche Overlap ◽  
Trophic Niche ◽  
Coral Host ◽  
Nitrogen Stable Isotope ◽  
Polyp Size ◽  
Carbon And Nitrogen ◽  
Algal Symbionts ◽  
Trophic Strategy

Ocean warming increases the incidence of coral bleaching, which reduces or eliminates the nutrition corals receive from their algal symbionts, often resulting in widespread mortality. In contrast to extensive knowledge on the thermal tolerance of coral-associated symbionts, the role of the coral host in bleaching patterns across species is poorly understood. Here, we applied a Bayesian analysis of carbon and nitrogen stable isotope data to determine the trophic niche overlap between corals and their symbionts and propose benchmark values that define autotrophy, heterotrophy, and mixotrophy. The amount of overlap between coral and symbiont niche was negatively correlated with polyp size and bleaching resistance. Our results indicated that as oceans warm, autotrophic corals lose their competitive advantage and thus are the first to disappear from coral reefs.

scholarly journals Shell Growth of Large Benthic Foraminifera under Heavy Metals Pollution: Implications for Geochemical Monitoring of Coastal Environments

2020 ◽  
Vol 17 (10) ◽  
pp. 3741 ◽  
Author(s):  
Nir Ben-Eliahu ◽  
Barak Herut ◽  
Eyal Rahav ◽  
Sigal Abramovich
Keyword(s):  
Heavy Metals ◽  
Shell Growth ◽  
Aquatic Organisms ◽  
Toxicity Tests ◽  
Proof Of Concept ◽  
Large Benthic Foraminifera ◽  
Algal Symbionts ◽  
Ecological Criteria ◽  
Heavy Metals Pollution ◽  
Pollution Events

This study was promoted by the recent efforts using larger benthic foraminiferal (LBF) shells geochemistry for the monitoring of heavy metals (HMs) pollution in the marine environment. The shell itself acts as a recorder of the ambient water chemistry in low to extreme HMs-polluted environments, allowing the monitoring of recent-past pollution events. This concept, known as sclerochronology, requires the addition of new parts (i.e., new shell) even in extreme pollution events. We evaluated the physiological resilience of three LBF species with different shell types and symbionts to enriched concentrations of Cd, Cu, and Pb at levels several folds higher than the ecological criteria maximum concentration (CMC) (165–166, 33–43, 1001–1206 µg L−1, respectively), which is derived from aquatic organisms’ toxicity tests. The physiological response of the holobiont was expressed by growth rates quantified by the addition of new chambers (new shell parts), and by the chlorophyll a of the algal symbionts. The growth rate decrease varied between 0% and 30% compared to the unamended control for all HMs tested, whereas the algal symbionts exhibited a general non-fatal but significant response to Pb and Cu. Our results highlight that shell growth inhibition of LBF is predicted in extreme concentrations of 57 × CMC of Cu and 523 × CMC of Cd, providing a proof of concept for shell geochemistry monitoring, which is currently not used in the regulatory sectors.

The Thermal Operating-Environment of a Lichen

1983 ◽  
Vol 15 (2) ◽  
pp. 191-207 ◽  
Author(s):  
K. A. Kershaw
Keyword(s):  
Boundary Layer ◽  
Thermal Tolerance ◽  
Thermal Environment ◽  
Extreme Temperature ◽  
Net Photosynthesis ◽  
Operating Environment ◽  
Temperature Optimum ◽  
Winter Temperatures ◽  
Lichen Woodland ◽  
Low Arctic

AbstractThe energy balance processes at a surface are reviewed in relation to the development of extreme temperature profiles that constitute the normal operating environment of a lichen. The specific nature of this operating environment, irrespective of altitude or latitude is emphasized and illustrated with a number of specific examples. These range from the ‘desert’ thermal environment following forest fire in low-arctic spruce-lichen woodland to boundary layer conditions at 2000 m, which is the environment of Rhizocarpon superficiale. The importance of winter temperatures and the ameliorating effects of snow cover and thallus colour are also related to the ecology and thermal environment of arctic and alpine lichens. Finally the thermal regime of corticolous and pendulous epiphytic lichens is discussed, again in terms of boundary layer and canopy microclimate. It is concluded that the thermal environment of a lichen largely interacts physiologically with the thermal tolerance limits of the dry thallus on one hand and the temperature optimum of net photosynthesis on the other.

scholarly journals Interactions between developmental and adult acclimation have distinct consequences for heat-tolerance and heat-stress recovery

2021 ◽  
Author(s):  
Quentin Willot ◽  
Ben Loos ◽  
John S. Terblanche
Keyword(s):  
Heat Stress ◽  
Heat Tolerance ◽  
Thermal Tolerance ◽  
Climatic Conditions ◽  
Distinct Pattern ◽  
Recovery Rates ◽  
Relative Contribution ◽  
Heat Hardening ◽  
Full Factorial Experimental Design ◽  
Post Stress

Developmental and adult thermal acclimation can have distinct, even opposite, effects on adult heat resistance in ectotherms. Yet, their relative contribution to heat-hardiness of ectotherms remains unclear despite the broad ecological implications thereof. Furthermore, the deterministic relationship between heat-knockdown and recovery from heat stress is poorly understood but significant for establishing causal links between climate variability and population dynamics. Here, using D. melanogaster in a full-factorial experimental design, we assess flies heat-tolerance in static stress assays, and document how developmental and adult acclimation interact with a distinct pattern to promote survival to heat-stress in adults. We show that warmer adult acclimation is the initial factor enhancing survival to constant stressful high temperatures in flies, but also that the interaction between adult and developmental acclimation becomes gradually more important to ensure survival as the stress persists. This provides an important framework revealing the dynamic interplay between these two forms of acclimation, that ultimately enhance thermal tolerance as a function of stress duration. Furthermore, by investigating recovery rates post-stress, we also show that the process of heat-hardening and recovery post heat knockdown are likely to be based on set of (at least partially) divergent mechanisms. This could bear ecological significance as a tradeoff may exist between increasing thermal tolerance and maximizing recovery rates post-stress, constraining population responses when exposed to variable and stressful climatic conditions.

scholarly journals Competitive traits of coral symbionts may alter the structure and function of the microbiome

2020 ◽  
Vol 14 (10) ◽  
pp. 2424-2432
Author(s):  
Shelby E. McIlroy ◽  
Jane C. Y. Wong ◽  
David M. Baker
Keyword(s):  
Temperature Stress ◽  
Thermal Tolerance ◽  
Niche Partitioning ◽  
Cell Replication ◽  
Algal Symbionts ◽  
Nutrient Assimilation ◽  
The Face ◽  
Increased Sensitivity ◽  
Species Specific ◽  
And Function

Abstract In the face of global warming and unprecedented coral bleaching, a new avenue of research is focused on relatively rare algal symbionts and their ability to confer thermal tolerance to their host by association. Yet, thermal tolerance is just one of many physiological attributes inherent to the diversity of symbiodinians, a result of millions of years of competition and niche partitioning. Here, we revealed that competition among cocultured symbiodinians alters nutrient assimilation and compound production with species-specific responses. For Cladocopium goreaui, a species ubiquitous within stable coral associations, temperature stress increased sensitivity to competition eliciting a shift toward investment in cell replication, i.e., putative niche exploitation. Meanwhile, competition led Durusdinium trenchii, a thermally tolerant “background” symbiodinian, to divert resources from immediate growth to storage. As such, competition may be driving the dominance of C. goreaui outside of temperature stress, the destabilization of symbioses under thermal stress, the repopulation of coral tissues by D. trenchii following bleaching, and ultimately undermine the efficacy of symbiont turnover as an adaptive mechanism.

Optimizing aerial environments for greenhouse rose production utilizing whole-plant net CO2 exchange data

1991 ◽  
Vol 71 (1) ◽  
pp. 253-261 ◽  
Author(s):  
J. Jiao ◽  
M. J. Tsujita ◽  
B. Grodzinski
Keyword(s):  
Dark Respiration ◽  
Net Photosynthesis ◽  
Co2 Exchange ◽  
Day Length ◽  
Daily Growth ◽  
Relative Contribution ◽  
Whole Plant ◽  
Nondestructive Measurements ◽  
Environment Modelling ◽  
Exchange Data

A daily growth model was developed for Samantha roses based on nondestructive measurements of whole-plant net CO2 exchange rate (NCER) under various aerial environmental conditions. Irradiance, CO2 concentration, and temperature accounted for 70, 20, and 5%, respectively, of the variance in whole-plant net photosynthesis explainable by a second-order polynomial model (R2 = 0.86). The predicted optimal temperatures for whole-plant net photosynthesis increased from 19 to 24 °C with increasing irradiance from 100 to 1200 μmol m−2 s−1 and CO2 concentration from 350 to 1500 μL L−1. Dark respiration rate increased exponentially with temperature and could be predicted by the Arrhenius equation. Even though respiratory carbon (C) loss at night increased linearly with daytime C gain, daily C gain (AC) was still proportional to daytime net photosynthesis. The relative contribution of irradiance (100–1200 μmol m−2s−1), day length (8–16 h), CO2 concentration (350–1500 μL L−1), day temperature (15–30 °C), and night temperature (15–25 °C) to plant daily growth was 64, 31, 4, 0.3, and 0.7%, respectively. Key words: Carbon balance, environment, modelling, photosynthesis, respiration, Rosa hybrida

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