scholarly journals Heatwaves during low tide are critical for the physiological performance of intertidal macroalgae under global warming scenarios

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Marta Román ◽  
Salvador Román ◽  
Elsa Vázquez ◽  
Jesús Troncoso ◽  
Celia Olabarria
Keyword(s):  
Global Warming ◽  
Iberian Peninsula ◽  
Air Temperature ◽  
Sublethal Effects ◽  
Seawater Temperature ◽  
Critical Factor ◽  
Physiological Performance ◽  
Air Temperatures ◽  
Cystoseira Tamariscifolia ◽  
The Impact

AbstractThe abundance and distribution of intertidal canopy-forming macroalgae are threatened by the increase in sea surface temperature and in the frequency and intensity of heatwaves caused by global warming. This study evaluated the physiological response of predominant intertidal macroalgae in the NW Iberian Peninsula (Bifurcaria bifurcata, Cystoseira tamariscifolia and Codium tomentosum) to increased seawater temperature during immersion and increased air temperatures during consecutive emersion cycles. We combined field mensuration and laboratory experiments in which we measured mortality, growth, maximum quantum yield and C:N content of the macroalgae. Air temperature was a critical factor in determining physiological responses and survivorship of all species, whereas high seawater temperature had sublethal effects. Cystoseira tamariscifolia suffered the greatest decreases in Fv/Fm, growth and the highest mortality under higher air temperatures, whereas C. tomentosum was the most resistant and resilient species. Two consecutive cycles of emersion under atmospheric heatwaves caused cumulative stress in all three macroalgae, affecting the physiological performance and increasing the mortality. The potential expansion of the warm-temperate species B. bifurcata, C. tamariscifolia and C. tomentosum in the NW Iberian Peninsula in response to increasing seawater temperature may be affected by the impact of increased air temperature, especially in a region where the incidence of atmospheric heatwaves is expected to increase.

scholarly journals The Impact of Infiltration on Heating Systems Dimensioning in Estonian Climate

2020 ◽  
Vol 172 ◽  
pp. 05004
Author(s):  
Raimo Simson ◽  
Taaniel Rebane ◽  
Martin Kiil ◽  
Martin Thalfeldt ◽  
Jarek Kurnitski
Keyword(s):  
Air Temperature ◽  
Indoor Air ◽  
Energy Performance ◽  
Simulation Software ◽  
Heat Losses ◽  
Climatic Data ◽  
Heating Systems ◽  
Air Temperatures ◽  
The Impact ◽  
Calculation Models

In this study we analysed the climatic conditions for infiltration estimation, different calculation methods and infiltration impact on heat load for heating systems dimensioning. To determine the wind conditions at low air temperatures of the coastal- and inland climatic zones in Estonia, 42 years of climatic data for Tallinn and Tartu were investigated. Calculation models with detailed air leakages were constructed of a single and two-storey detached house using dynamic simulation software IDA ICE. Simulations were carried out with the constructed calculation models, simulating various wind and sheltering conditions to determine the heating load of the buildings under measured wind conditions at the design external air temperatures. The simulation results were compared with results calculated with European Standard EN 12831:2017, methodology given in the Estonian regulation for calculating energy performance of buildings and with simulations using the default settings in IDA ICE based on the ASHRAE design day conditions. The percentage of heat losses caused by infiltration was found as 13-16% of all heat losses for the studied buildings. Simulations with historical climate periods showed that even in windy weather conditions the heating system dimensioned by the methods analysed may not be able to provide the required indoor air temperature. Analysis using the coldest and windiest periods showed that when systems are dimensioned by the studied methods, the highest decline in indoor air temperature occurs on the windiest day and not on the coldest day. The impact of high wind speeds and low sheltering conditions resulted up to 50% of all heat losses.

scholarly journals The Impact of Site Extremes on the Onset of Phenological Phases of Selected Tree Species

2014 ◽  
Vol 62 (5) ◽  
pp. 1117-1124
Author(s):  
Jana Škvareninová
Keyword(s):  
Air Temperature ◽  
Tree Species ◽  
Soil Depth ◽  
Average Length ◽  
Growing Season ◽  
Corylus Avellana ◽  
Extreme Conditions ◽  
Air Temperatures ◽  
The Impact ◽  
Phenological Phases

In the years 2007–2013 we performed phenological observations of common hazel (Corylus avellana L.), blackthorn (Prunus spinosa L.), and hawthorn (Crataegus oxyacantha L.) at two locations of central Slovakia situated at elevations of 300 m and 530 m a.s.l. The phenophase of first leaves of all tree species started in the second half of April on average, and was conditioned by the average daily air temperatures above 0 °C. The earliest onset was observed at both locations in 2007 due to the highest average air temperature during the observed period, which in March reached the value of 6.1 °C. Colouring of leaves started in the second and third decades of September. Both phenophases began earlier at the location situated at the higher elevation due to the effect of aspect, terrain, and soil depth. During the last 7 years, the average length of the growing season of tree species situated at an elevation of 300 m was from 136 to 152 days, in more extreme conditions at an elevation of 530 m the growing season was shorter by 12 days in the case of blackthorn and by 5 days in the case of hawthorn.

scholarly journals Recent extreme air temperature changes in Montenegro

2015 ◽  
Vol 95 (4) ◽  
pp. 53-66 ◽  
Author(s):  
Dragan Buric ◽  
Vladan Ducic ◽  
Jovan Mihajlovic ◽  
Jelena Lukovic ◽  
Jovan Dragojlovic
Keyword(s):  
Global Warming ◽  
Air Temperature ◽  
General Idea ◽  
Extreme Weather Events ◽  
Climate Indices ◽  
Temperature Extremes ◽  
Temperature Changes ◽  
Air Temperatures ◽  
Weather Events ◽  
The World

The studies show that the changes in intensity and frequency of the extreme weather events have been registered in many regions of the world. This paper gives an analysis of the change of 12 air temperature parameters, out of which 9 are climate indices. The indices suggested by WMO-CCL/CLIVAR have been used in order to investigate the changes in temperature extremes. The research related to the topic has been carried out by using the data from 23 meteorological stations for the 1951 - 2010 period and calculations have been done on the seasonal level. The results show that the maximum and minimum air temperatures, which have ?warmer values?, are becoming more frequent on the territory of Montenegro which corresponds to the general idea of global warming.

scholarly journals Effects of different fertilizer systems and hydrothermal factors on microbial activity in the chernozem in Ukraine

2018 ◽  
Vol 26 (4) ◽  
pp. 309-315 ◽  
Author(s):  
O. S. Demyanyuk ◽  
О. V. Sherstoboeva ◽  
A. A. Bunas ◽  
O. V. Dmitrenko
Keyword(s):  
Microbial Biomass ◽  
Winter Wheat ◽  
Air Temperature ◽  
Mineral Fertilizers ◽  
Soil Parameters ◽  
Natural Ecosystem ◽  
Air Temperatures ◽  
Organic Mineral ◽  
Close Relationship ◽  
The Impact

Groups of microorganisms in soils perform the role of global biogeochemical membrane which provides metabolism of substances and energy between the pedosphere, lithosphere, hydrosphere and living organisms. Сlimate change has resulted in a complex combination of unpredictable changeability of the environment, which is a serious test for the stability and productivity for the natural and anthropogenically transformed ecosystems. Changeability of the hydrothermal factors causes serious changes in the structure and metabolic activity of soil microorganisms, the quality and properties of soil. We studied the impact of hydrothermal factors on the content of carbon, microbial biomass and organic substance in deep chernozem of a natural ecosystem (fallow) and an agroecosystem under different systems of fertilization of winter wheat. A close relationship (r = 0.69–0.79) was determined between the content of microbial biomass in soil and hydrothermal factors (air temperature and moisture). Excessive drought and high parameters of air temperature led to decrease in the content of microbial biomass by 1.5–2.8 times compared to the years with optimum parameters of hydrothermal regime (HTC = 1.0). Leveling out the impact of high temperatures on the productivity of the soil microbiota occurs at a sufficient amount of moisture, and also available nutrients. Drought (HTC = 0.4) and excessive moisture (HTC = 2.0) following heightened air temperatures reduce the release of СО2 from soil. Fallow soil usually has a high content of microbial carbon in the organic compounds of soil (Сmic/Сorg was 2%). In the agroecosystem, there was recorded a decrease by 26–32% of the Сmic specific share in the content of the organic compound of the soil compared to the natural analogue. With organic and organic-mineral systems of fertilization, an increase in Сmic/Сorg parameter occurs and the soil parameters become close to the soil of a natural ecosystem. The calculated ecological coefficients of the orientation of microbial processes in soil indicate a possibility of a balanced functioning of the microbial group and introducing organic and organic-mineral fertilizers, creating optimum conditions for the productivity of winter wheat.

Late 20th century increase in northern Svalbard glacier-derived runoff tracked by encrusting coralline algae

2020 ◽  
Author(s):  
Steffen Hetzinger ◽  
Jochen Halfar ◽  
Zoltan Zajacz ◽  
Marco Möller ◽  
Max Wisshak
Keyword(s):  
Global Warming ◽  
Air Temperature ◽  
Surface Air Temperature ◽  
High Arctic ◽  
Climate System ◽  
Coralline Algae ◽  
The Arctic ◽  
Surface Ocean ◽  
The Impact ◽  
Arctic Surface

<p>The Arctic cryosphere is changing at a rapid pace due to global warming and the large-scale changes observed in the Arctic during the past decades exert a strong influence throughout the global climate system. The warming of Arctic surface air temperatures is more than twice as large as the global average over the last two decades and recent events indicate new extremes in the Arctic climate system, e.g. for the last five years Arctic annual surface air temperature exceeded that of any year since 1900 AD. Northern Spitsbergen, Svalbard, located in the High Arctic at 80°N, is a warming hotspot with an observed temperature rise of ~6°C over the last three decades indicating major global warming impacts. However, even the longest available datasets on Svalbard climatic conditions do not extend beyond the 1950s, inhibiting the study of long-term natural variability before anthropogenic influence. Ongoing climate trends strongly affect the state of both glaciers and seasonal snow in Svalbard. Modeled data suggest a marked increase in glacier runoff during recent decades in northern Svalbard. However, observational data are sparse and short and the potential effects on the surface ocean are unclear.<br>This study focuses on the ultra-high-resolution analysis of calcified coralline algal buildups growing attached to the shallow seafloor along Arctic coastlines. Analysis of these new annually-layered climate archives is based on the long-lived encrusting coralline algae <em>Clathromorphum compactum</em>, providing a historic perspective on recently observed changes. Here, we present a 200-year record of past surface ocean variability from Mosselbukta, Spitsbergen, northern Svalbard. By using algal Ba/Ca ratios as a proxy for past glacier-derived meltwater input, we investigate past multi-decadal-scale fluctuations in land-based freshwater contributions to the ocean surface layer. Our records, based on multiple coralline algal specimens, show a strong and statistically significant increasing trend in algal Ba/Ca ratios from the 1990s onwards, suggesting a drastic increase in land-based runoff at Mosselbukta. The drastic rate of increase is unprecedented during the last two centuries, directly capturing the impact of amplified surface air temperature warming on coastal high Arctic surface ocean environments.</p><p> </p>

scholarly journals The impact of indoor air temperature on the executive functions of human brain and the physiological responses of body

2019 ◽  
Vol 9 (1) ◽  
pp. 55-64 ◽  
Author(s):  
Ali Mohammad Abbasi ◽  
Majid Motamedzadeh ◽  
Mohsen Aliabadi ◽  
Rostam Golmohammadi ◽  
Leili Tapak
Keyword(s):  
Executive Functions ◽  
Human Brain ◽  
Air Temperature ◽  
Physiological Responses ◽  
Heart Beat ◽  
Temperature Conditions ◽  
Beat Rate ◽  
Air Temperatures ◽  
Heart Beat Rate ◽  
The Impact

Background: This study aimed to investigate the effect size (ES) of air temperature on the executive functions of human brain and body physiological responses. Methods: In this empirical study, the participants included 35 male students who were exposed to 4 air temperature conditions of 18°C, 22°C, 26°C and 30°C in 4 separate sessions in an air conditioning chamber. The participants were simultaneously asked to take part in the N-backtest. The accuracy, electrocardiogram (ECG) signals and the respiration rate were recorded to determine the effect of air temperature. Results: Compared to moderate air temperatures (22°C), high (30°C) and low (18°C) air temperatures had a much more profound effect on changes in heart beat rate, the accuracy of brain executive functions and the response time to stimuli. There were statistically significant differences in the accuracy by different workload levels and various air temperature conditions(P<0.05). Although the heart beat rate index, the ratio between low frequency and high frequency (LF/HF), and the respiratory rate were more profoundly affected by the higher and lower air temperatures than moderate air temperatures (P<0.05), this effect was not statistically significant, which may be due to significant reduction in the standard deviation of normal-to normal intervals (SNND) and the root of mean squared difference between adjacent normal heart beat (N-N) intervals (RMSSD) (P>0.05). Conclusion: The results confirmed that the unfavorable air temperatures may considerably affect the physiological responses and the cognitive functions among indoor employees.Therefore, providing them with thermal comfort may improve their performance within indoor environments.

scholarly journals Impact of Seasonal Changes of Precipitation and Air Temperature on Clay Excavation

2019 ◽  
Vol 11 (22) ◽  
pp. 6368 ◽  
Author(s):  
Denis Težak ◽  
Božo Soldo ◽  
Bojan Đurin ◽  
Nikola Kranjčić
Keyword(s):  
Air Temperature ◽  
Drought Index ◽  
Clay Soil ◽  
Daily Precipitation ◽  
Partial Sums ◽  
Air Temperatures ◽  
Time Period ◽  
Global Exploitation ◽  
Soil Excavation ◽  
The Impact

Excavation of clay soil is one of the most important economic branches in the northern part of Croatia. The impact of clay soil in Croatia compared to the global exploitation fields of clay soil is negligible. Modern methods of clay excavation during winter months due to negligible amounts are not profitable. Therefore, it is important to optimize clay soil excavation throughout the year to increase the efficiency of exploitation and increase profits. In the case of large amounts of precipitation (rain), clay absorbs water and becomes grain. For this reason, access to the exploitation field and excavation itself becomes impossible. Air temperature also plays an important role in excavation. Long-lasting low air temperatures below 0 °C during the winter months result in clay frost. As a result, excavation cannot occur at that time. The paper describes a new method of modeling the precipitation and air temperature on the exploitation fields of clay in Northwest Croatia on the exploitation fields of Cukavec and Cukavec II. The method involves the calculation of the drought index and use of the rescaled adjusted partial sums (RAPS) statistical method and its application on a time series of total daily precipitation and average daily temperatures as a climatic indicator of any observed area. Using this process, it is possible to determine the time period of the year when clay soil can be excavated.

scholarly journals Ideas and perspectives: Heat stress: more than hot air

2016 ◽  
Author(s):  
Hans J. De Boeck ◽  
Helena Van De Velde ◽  
Toon De Groote ◽  
Ivan Nijs
Keyword(s):  
Heat Stress ◽  
Air Temperature ◽  
Heat Waves ◽  
Balance Model ◽  
Plant Responses ◽  
Atmospheric Conditions ◽  
Change Models ◽  
Wind Speeds ◽  
Air Temperatures ◽  
The Impact

Abstract. Climate change models project an important increase in the frequency and intensity of heat waves. In gauging the impact on plant responses, much of the focus has been on air temperatures while a critical analysis of leaf temperatures during heat extremes has not been made. Nevertheless, direct physiological consequences from heat depend primarily on leaf rather than on air temperatures. We discuss how the interplay between various environmental variables and the plants' stomatal response affects leaf temperatures and the potential for heat stress by making use of both an energy balance model and field data. The results demonstrate that this interplay between plants and environment can cause leaf temperatures fluctuations in excess of 10 °C (for narrow leaves) to even 20 °C (for big broad leaves) at the same air temperature. In general, leaves tended to heat up when radiation was high and when stomates were closed, as expected. But perhaps counterintuitively, also high air humidity raised leaf temperatures, while humid conditions are typically regarded as benign with respect to plant survival since they limit water loss. High wind speeds brought the leaf temperature closer to the air temperature, which can imply either cooling or warming (i.e. abating or reinforcing heat stress) depending on other prevailing conditions. The results thus indicate that heat waves characterized by similar extreme air temperatures may pose little danger under some atmospheric conditions, but could be lethal in other cases. The trends illustrated here should give ecologists and agronomists a more informed indication about which circumstances are most conductive for heat stress to occur.

scholarly journals The implications of climate change conditions in the pavement design

2021 ◽  
Author(s):  
Dominika Hodáková ◽  
Andrea Zuzulová ◽  
Silvia Cápayová ◽  
Tibor Schlosser
Keyword(s):  
Climate Change ◽  
Air Temperature ◽  
Input Parameter ◽  
Road Construction ◽  
Climatic Conditions ◽  
Design Solution ◽  
Model Calculations ◽  
Air Temperatures ◽  
The Impact

The design of pavement structure is as a set of several activities related to the design of road construction, dimension and model calculations. This includes calculations of load effects, taking into account the properties of the materials, the subgrade conditions, and the climatic conditions. The measurements of climatic conditions in Slovakia were the basis for assessing changes in average daily air temperatures in individual seasons. Since the 19th century we have seen in Slovakia an increase in the average air temperature of 1.5 ° C. Currently, there are scenarios of climate change until 2100. An increase in air temperature is assumed, with an increase in average monthly temperatures of 2.0 to 4.8 °C. In road construction, as well as in other areas of engineering, we must respond to current climate change and also to expected changes. The average annual air temperature and the frost index are the critical climatic characteristics are the main for the design (input parameter) and evaluation of pavement. From the practical side it is possible to use the design maps of average annual air temperature and frost index according to STN 73 6114 from year 1997. In cooperation with the Slovak Hydrometeorological Institute from the long-term monitoring of temperatures, different meteorological characteristics were measured in the current period. From the measurements of twelve professional meteorological stations for the period 1971 to 2020, the dependence between two variables in probability theory is derived. The average annual air temperatures used for prognoses are collected from long-term measurements (fifty years). The design of road constructions and calculations of road construction models, which are in the system design solution (comparative calculations of asphalt pavement- and cement-concrete pavement models), we have also tested road construction materials - especially asphalt mixtures. The results were used to correct the values of input data, design criteria, as well as measures to reduce the impact of changes in climate conditions.

Nest stage, wind speed, and air temperature affect the nest defence behaviours of burrowing owls

2004 ◽  
Vol 82 (5) ◽  
pp. 707-713 ◽  
Author(s):  
Ryan J Fisher ◽  
Ray G Poulin ◽  
L Danielle Todd ◽  
R M Brigham
Keyword(s):  
Wind Speed ◽  
Air Temperature ◽  
Reproductive Investment ◽  
Weather Conditions ◽  
Nest Defence ◽  
Athene Cunicularia ◽  
Burrowing Owls ◽  
Burrowing Owl ◽  
Air Temperatures ◽  
The Impact

The effect of nest stage on nest defence responses has been fairly well established but the impact of weather conditions has been largely ignored. We examined the effects of nest stage, number of previous visits, wind speed, and air temperature on burrowing owl (Athene cunicularia (Molina, 1782)) defence of nests from a human intruder. We found that burrowing owls changed nest defence tactics from retreat behaviour to more confrontational behaviour once eggs hatched. Aggressiveness was significantly reduced as wind velocity increased and when temperatures were warmer. We found no evidence for a change in owl defence behaviour with the number of previous visits to a nest. Although not statistically significant, there was a tendency for burrowing owls to allow closer approaches and to not retreat as far once eggs had hatched. Wind speed did not have an effect on retreat or approach distances, and owls allowed us to get significantly closer to the nest before retreating when air temperatures were warm. There are a multitude of factors that could affect nesting success and thus fitness of birds, but our study shows that routine climatic events such as warm weather had a measurable impact on how a bird defended its reproductive investment.

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