scholarly journals Thermal Performance Reflects Evolutionary Legacies of Seaweeds and Seagrasses Across a Regional Climate Gradient

2021 ◽  
Author(s):  
Scott Bennett ◽  
Raquel Vaquer-Sunyer ◽  
Gabriel Jorda ◽  
Marina Forteza ◽  
Guillem Roca ◽  
...  
Keyword(s):  
Thermal Performance ◽  
Thermal Sensitivity ◽  
Regional Climate ◽  
Posidonia Oceanica ◽  
Species Variation ◽  
Thermal Limits ◽  
Cystoseira Compressa ◽  
Safety Margins ◽  
Summer Temperatures ◽  
Edge Populations

Abstract Comparative patterns in thermal performance between populations have fundamental implications for a species thermal sensitivity to warming and extreme events. Despite this, within-species variation in thermal performance is seldom measured. Here we compare within-species variation in thermal performance across the Mediterranean Sea, with between-species variation within communities, for two species of seagrass (Posidonia oceanica and Cymodocea nodosa) and two species of seaweed (Padina pavonica and Cystoseira compressa). Experimental populations from four locations representing approximately 75% of each species global distribution and a 6ºC gradient in summer temperatures were exposed to 10 temperature treatments (15ºC to 36ºC), reflecting median, maximum and future temperatures. Thermal performance displayed the greatest variability between species, with optimal temperatures differing by over 10ºC within the same location. Within-species differences in thermal performance were also important for P. oceanica which displayed large thermal safety margins within cool and warm-edge populations and small safety margins within central populations. Overall, experimental upper thermal limits reflected genus-level realised thermal limits, more than realised species-limits or maximum local temperatures. Our findings suggest patterns of thermal performance in Mediterranean seagrasses and seaweeds retain deep ‘pre-Mediterranean’ evolutionary legacies, resulting in unexpected patterns of vulnerability to warming within benthic marine communities.

scholarly journals Phytoplankton thermal responses adapt in the absence of hard thermodynamic constraints

2018 ◽  
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.

Vulnerability to global warming of a Critically Endangered lizard from the Monte Desert, Patagonia Argentina

2021 ◽  
Author(s):  
María Victoria Brizio ◽  
Facundo Cabezas-Cartes ◽  
Jimena Beatriz Fernández ◽  
Rodrigo Gómez Alés ◽  
Luciano Javier Avila
Keyword(s):  
Global Warming ◽  
Thermal Sensitivity ◽  
Thermal Conditions ◽  
Sun Exposure ◽  
Critically Endangered ◽  
Body Temperatures ◽  
Monte Desert ◽  
Safety Margins ◽  
Environmental Temperatures

Reptiles’ body temperature is strongly influenced by the thermal quality of microhabitats, exploiting the favourable environmental temperatures, and avoiding exposure to extreme thermal conditions. For these reasons, reptiles’ populations are considered to be especially vulnerable to changes in environmental temperatures produced by climate change. Here, we study the thermal physiology of the Critically Endangered lizard Liolaemus cuyumhue Avila, Morando, Perez and Sites, 2009. We hypothesise that, (1) there is a thermal coadaptation between optimal temperature for locomotor performance of L. cuyumhue and its thermal preference; (2) L. cuyumhue lives in an environment with low thermal quality; (3) a raise in environmental temperatures due to global warming will impose a decrement in locomotor speed represented by lower warming tolerance and narrower thermal safety margins, increasing their already high vulnerability. We registered field body temperatures (Tb), preferred body temperatures (Tpref), the operative (Te), and the thermal sensitivity of locomotion at different body temperatures. Our results indicate that this lizard is not currently under environmental stress or exceeding its thermal limits, but that it is thermorregulating below Tpref to avoid overheating, and that an increase in environmental temperature higher than 3.5 °C will strongly affect the use of microhabitats with direct sun exposure.

Upper thermal limits and warming safety margins of coastal marine species – Indicator baseline for future reference

2019 ◽  
Vol 102 ◽  
pp. 644-649 ◽  
Author(s):  
Catarina Vinagre ◽  
Marta Dias ◽  
Rui Cereja ◽  
Francisca Abreu-Afonso ◽  
Augusto A.V. Flores ◽  
...  
Keyword(s):  
Marine Species ◽  
Thermal Limits ◽  
Coastal Marine ◽  
Safety Margins ◽  
Future Reference

scholarly journals Warming effect on nitrogen fixation in Mediterranean macrophyte sediments

2019 ◽  
Vol 16 (1) ◽  
pp. 167-175 ◽  
Author(s):  
Neus Garcias-Bonet ◽  
Raquel Vaquer-Sunyer ◽  
Carlos M. Duarte ◽  
Núria Marbà
Keyword(s):  
N2 Fixation ◽  
Thermal Sensitivity ◽  
Thermal Response ◽  
Sharp Decrease ◽  
Posidonia Oceanica ◽  
Global Ocean ◽  
Thermal Dependence ◽  
High Productivity ◽  
Marine Macrophytes ◽  
The Impact

Abstract. The Mediterranean Sea is warming faster than the global ocean, with important consequences for organisms and biogeochemical cycles. Warming is a major stressor for key marine benthic macrophytes. However, the effect of warming on marine N2 fixation remains unknown, despite the fact that the high productivity of macrophytes in oligotrophic waters is partially sustained by the input of new nitrogen (N) into the system by N2 fixation. Here, we assess the impact of warming on the N2 fixation rates of three key marine macrophytes: Posidonia oceanica, Cymodocea nodosa, and Caulerpa prolifera. We experimentally measured N2 fixation rates in vegetated and bare sediments at temperatures encompassing current summer mean (25 and 27 ∘C), projected summer mean (29 and 31 ∘C), and projected summer maximum (33 ∘C) seawater surface temperatures (SSTs) by the end of the century under a scenario of moderate greenhouse gas emissions. We found that N2 fixation rates in vegetated sediments were 2.8-fold higher than in bare sediments at current summer mean SST, with no differences among macrophytes. Currently, the contribution of N2 fixation to macrophyte productivity could account for up to 7 %, 13.8 %, and 1.8 % of N requirements for P. oceanica, C. nodosa, and C. prolifera, respectively. We show the temperature dependence of sediment N2 fixation rates. However, the thermal response differed for vegetated sediments, in which rates showed an optimum at 31 ∘C followed by a sharp decrease at 33 ∘C, and bare sediments, in which rates increased along the range of the experimental temperatures. The activation energy and Q10 were lower in vegetated than bare sediments, indicating the lower thermal sensitivity of vegetated sediments. The projected warming is expected to increase the contribution of N2 fixation to Mediterranean macrophyte productivity. Therefore, the thermal dependence of N2 fixation might have important consequences for primary production in coastal ecosystems in the context of warming.

scholarly journals Thermal performance curves reveal shifts in optima, limits and breadth in early life

2020 ◽  
Vol 223 (22) ◽  
pp. jeb233254
Author(s):  
Adriana P. Rebolledo ◽  
Carla M. Sgrò ◽  
Keyne Monro
Keyword(s):  
Embryo Development ◽  
Thermal Performance ◽  
Early Life ◽  
Thermal Sensitivity ◽  
Life Stage ◽  
Life Stages ◽  
Parametric Bootstrapping ◽  
Performance Curves ◽  
Survival And Reproduction ◽  
Mixed Modelling

ABSTRACTUnderstanding thermal performance at life stages that limit persistence is necessary to predict responses to climate change, especially for ectotherms whose fitness (survival and reproduction) depends on environmental temperature. Ectotherms often undergo stage-specific changes in size, complexity and duration that are predicted to modify thermal performance. Yet performance is mostly explored for adults, while performance at earlier stages that typically limit persistence remains poorly understood. Here, we experimentally isolate thermal performance curves at fertilization, embryo development and larval development stages in an aquatic ectotherm whose early planktonic stages (gametes, embryos and larvae) govern adult abundances and dynamics. Unlike previous studies based on short-term exposures, responses with unclear links to fitness or proxies in lieu of explicit curve descriptors (thermal optima, limits and breadth), we measured performance as successful completion of each stage after exposure throughout, and at temperatures that explicitly capture curve descriptors at all stages. Formal comparisons of descriptors using a combination of generalized linear mixed modelling and parametric bootstrapping reveal important differences among life stages. Thermal performance differs significantly from fertilization to embryo development (with thermal optimum declining by ∼2°C, thermal limits shifting inwards by ∼8–10°C and thermal breadth narrowing by ∼10°C), while performance declines independently of temperature thereafter. Our comparisons show that thermal performance at one life stage can misrepresent performance at others, and point to gains in complexity during embryogenesis, rather than subsequent gains in size or duration of exposure, as a key driver of thermal sensitivity in early life.

A Quantitative Holocene Climatic Record from Diatoms in Northern Fennoscandia

2000 ◽  
Vol 54 (2) ◽  
pp. 284-294 ◽  
Author(s):  
Atte Korhola ◽  
Jan Weckström ◽  
Lasse Holmström ◽  
Panu Erästö
Keyword(s):  
Regional Climate ◽  
Ice Core ◽  
Ice Age ◽  
Calibration Model ◽  
Subarctic Lakes ◽  
Northern Fennoscandia ◽  
Summer Temperatures ◽  
Climatic Record ◽  
Climate Events

A diatom-based calibration model for predicting summer temperatures was developed using climatically sensitive subarctic lakes in northern Fennoscandia. The model was applied to a sediment core from a treeline lake to infer trends in Holocene climate. The record exhibits long-term variations, as well as a series of shorter-term fluctuations on a time scale of centuries. Summers were warmest in the area about 6200 cal yr B.P. and featured distinct cooling episodes around 8300, 7200, 4200, 3000, and 400 cal yr B.P., most of these coinciding with some known climate events (e.g., the 8200 cal yr B.P. event and the Little Ice Age). The similarity of the observed shifts with the pacings of climate events from marine and ice-core records represents evidence for coupled ocean–atmosphere forcing of the regional climate.

scholarly journals Integrating within-species variation in thermal physiology into climate change ecology

2019 ◽  
Vol 374 (1778) ◽  
pp. 20180550 ◽  
Author(s):  
Scott Bennett ◽  
Carlos M. Duarte ◽  
Núria Marbà ◽  
Thomas Wernberg
Keyword(s):  
Climate Change ◽  
Global Climate ◽  
Thermal Sensitivity ◽  
High Sensitivity ◽  
Population Level ◽  
Marine Organisms ◽  
Ocean Warming ◽  
Species Variation ◽  
Thermal Physiology ◽  
Physiological Diversity

Accurately forecasting the response of global biota to warming is a fundamental challenge for ecology in the Anthropocene. Within-species variation in thermal sensitivity, caused by phenotypic plasticity and local adaptation of thermal limits, is often overlooked in assessments of species responses to warming. Despite this, implicit assumptions of thermal niche conservatism or adaptation and plasticity at the species level permeate the literature with potentially important implications for predictions of warming impacts at the population level. Here we review how these attributes interact with the spatial and temporal context of ocean warming to influence the vulnerability of marine organisms. We identify a broad spectrum of thermal sensitivities among marine organisms, particularly in central and cool-edge populations of species distributions. These are characterized by generally low sensitivity in organisms with conserved thermal niches, to high sensitivity for organisms with locally adapted thermal niches. Important differences in thermal sensitivity among marine taxa suggest that warming could adversely affect benthic primary producers sooner than less vulnerable higher trophic groups. Embracing the spatial, temporal and biological context of within-species variation in thermal physiology helps explain observed impacts of ocean warming and can improve forecasts of climate change vulnerability in marine systems. This article is part of the theme issue ‘Physiological diversity, biodiversity patterns and global climate change: testing key hypotheses involving temperature and oxygen’.

scholarly journals Social cues can push amphibious fish to their thermal limits

2018 ◽  
Vol 14 (10) ◽  
pp. 20180492 ◽  
Author(s):  
Suzanne Currie ◽  
Glenn J. Tattersall
Keyword(s):  
Social Interactions ◽  
Physical Environment ◽  
Critical Thermal Maximum ◽  
Social Stimuli ◽  
Terrestrial Environment ◽  
Thermal Limits ◽  
Thermal Maximum ◽  
Safety Margins ◽  
Kryptolebias Marmoratus ◽  
Mangrove Rivulus

Social context can impact how animals respond to changes in their physical environment. We used an aggressive, amphibious fish, the mangrove rivulus ( Kryptolebias marmoratus ) with environmentally determined sociality to test the hypothesis that social interactions would push fish to their thermal limits. We capitalized on the propensity of rivulus to emerge from warming water and demonstrated that social stimuli, produced by their reflection, increased emersion threshold without changing the critical thermal maximum, effectively diminishing thermal safety margins. When rivulus were denied air access, surface behaviours dramatically increased, supplanting social interactions. This suggests that assessing the terrestrial environment is crucially important. We conclude that social stimulation narrows the scope for survival in naturally stressful conditions.

Experimental mixing of a north-temperate lake: testing the thermal limits of a cold-water invasive fish

2015 ◽  
Vol 72 (6) ◽  
pp. 926-937 ◽  
Author(s):  
Zach J. Lawson ◽  
M. Jake Vander Zanden ◽  
Colin A. Smith ◽  
Emily Heald ◽  
Thomas R. Hrabik ◽  
...  
Keyword(s):  
Cold Water ◽  
Thermal Sensitivity ◽  
Field Testing ◽  
Population Declines ◽  
Rainbow Smelt ◽  
Thermal Habitat ◽  
Thermal Thresholds ◽  
Adult Age ◽  
Intrapopulation Variation ◽  
Thermal Limits

Species’ thermal limits play a key role in determining spatial distributions and understanding their response to changing environments. Manipulation of thermal habitat is a potential avenue of exploration for management of invasive species such as the cold-water rainbow smelt (Osmerus mordax), which has adverse effects on native fish communities in central North American inland lakes. In an effort to test the thermal limits and selectively eradicate rainbow smelt, we experimentally mixed Crystal Lake, Wisconsin, USA, during summer of 2012 and 2013 to warm the hypolimnion and eliminate cold-water habitat. This whole-ecosystem manipulation allowed for field testing of published thermal thresholds reported for rainbow smelt. The rainbow smelt population responded to the thermal manipulation by exhibiting unexpected shifts in behavior, intrapopulation divergence in body condition, and significant population declines. Small individuals of each adult age-class tended to survive the manipulation, and the population persisted despite high mortality rates. Our results indicate a high degree of size-based intrapopulation variation in thermal sensitivity for this species. Our findings also raise questions regarding applicability of lab- and model-derived thermal limits to field scenarios, highlighting a need for further field evaluations of species’ thermal limits.

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