scholarly journals Response of psychrophilic plant endosymbionts to experimental temperature increase

2020 ◽  
Vol 7 (12) ◽  
pp. 201405
Author(s):  
Carolina Seas ◽  
Priscila Chaverri
Keyword(s):  
Global Warming ◽  
Temperature Increase ◽  
Fungal Endophytes ◽  
Growth Curves ◽  
High Elevation ◽  
Trophic Levels ◽  
Initial Growth ◽  
Endemic Plant ◽  
Symbiotic Relationships ◽  
Microbial Symbionts

Countless uncertainties remain regarding the effects of global warming on biodiversity, including the ability of organisms to adapt and how that will affect obligate symbiotic relationships. The present study aimed to determine the consequences of temperature increase in the adaptation of plant endosymbionts (endophytes) that grow better at low temperatures (psychrophilic). We isolated fungal endophytes from a high-elevation (paramo) endemic plant, Chusquea subtessellata . Initial growth curves were constructed at different temperatures (4–25°C). Next, experiments were carried out in which only the psychrophilic isolates were subjected to repeated increments in temperature. After the experiments, the final growth curves showed significantly slower growth than the initial curves, and some isolates even ceased to grow. While most studies suggest that the distribution of microorganisms will expand as temperatures increase because most of these organisms grow better at 25°C, the results from our experiments demonstrate that psychrophilic fungi were negatively affected by temperature increases. These outcomes raise questions concerning the potential adaptation of beneficial endosymbiotic fungi in the already threatened high-elevation ecosystems. Assessing the consequences of global warming at all trophic levels is urgent because many species on Earth depend on their microbial symbionts for survival.

Does past contact reduce the degree of mutualism in the Alnus rubra - Frankia symbiosis?

1999 ◽  
Vol 77 (3) ◽  
pp. 434-441 ◽  
Author(s):  
John H Markham ◽  
Chris P Chanway
Keyword(s):  
Soil Nitrogen ◽  
Vascular Plants ◽  
Nitrogen Isotopes ◽  
High Elevation ◽  
Plant Performance ◽  
Alnus Rubra ◽  
Fixed Nitrogen ◽  
Symbiotic Relationships ◽  
Microbial Symbionts ◽  
Whole Plants

Although most vascular plants have symbiotic relationships with soil microbes, and there is an extensive theoretical literature on the evolution of mutualism, there has been little experimental examination of the evolution of mutualism between plants and their microbial symbionts. We inoculated red alder (Alnus rubra Bong.) seedlings from three high- and three low-elevation populations with crushed nodule suspensions containing the nitrogen fixing bacterium Frankia from either the parent trees (familiar strains) or the other plant population sampled within the parent watershed (unfamiliar strains). The inoculated seedlings were planted on three high- and three low-elevation sites. Growth was monitored over the second and third year following planting, after which the whole plants were harvested. The proportion of nitrogen derived from fixation was estimated from the ratio of stable nitrogen isotopes in the harvested leaves. On low-elevation sites, which had high soil nitrogen, plants with familiar Frankia strains were half the size and derived less fixed nitrogen from their symbionts compared with plants inoculated with unfamiliar Frankia strains. On high-elevation sites, which had low soil nitrogen, the type of inoculum had little effect on plant performance, although plants with familiar inoculum were consistently larger than plants with unfamiliar inoculum. These results suggest that the degree of mutualism in this symbiosis depends on environmental conditions and may decrease with time.Key words: coevolution, Frankia, Alnus rubra, mutualism, nitrogen fixation, symbiosis.

scholarly journals Tree Diversity Reduces Fungal Endophyte Richness and Diversity in a Large-Scale Temperate Forest Experiment

Diversity ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 234 ◽  
Author(s):  
Eric A. Griffin ◽  
Joshua G. Harrison ◽  
Melissa K. McCormick ◽  
Karin T. Burghardt ◽  
John D. Parker
Keyword(s):  
Phylogenetic Diversity ◽  
Large Scale ◽  
High Throughput Sequencing ◽  
Spatial Scales ◽  
Fungal Endophytes ◽  
Fungal Endophyte ◽  
Tree Diversity ◽  
Trophic Levels ◽  
Community Diversity ◽  
And Function

Although decades of research have typically demonstrated a positive correlation between biodiversity of primary producers and associated trophic levels, the ecological drivers of this association are poorly understood. Recent evidence suggests that the plant microbiome, or the fungi and bacteria found on and inside plant hosts, may be cryptic yet important drivers of important processes, including primary production and trophic interactions. Here, using high-throughput sequencing, we characterized foliar fungal community diversity, composition, and function from 15 broadleaved tree species (N = 545) in a recently established, large-scale temperate tree diversity experiment using over 17,000 seedlings. Specifically, we tested whether increases in tree richness and phylogenetic diversity would increase fungal endophyte diversity (the “Diversity Begets Diversity” hypothesis), as well as alter community composition (the “Tree Diversity–Endophyte Community” hypothesis) and function (the “Tree Diversity–Endophyte Function” hypothesis) at different spatial scales. We demonstrated that increasing tree richness and phylogenetic diversity decreased fungal species and functional guild richness and diversity, including pathogens, saprotrophs, and parasites, within the first three years of a forest diversity experiment. These patterns were consistent at the neighborhood and tree plot scale. Our results suggest that fungal endophytes, unlike other trophic levels (e.g., herbivores as well as epiphytic bacteria), respond negatively to increasing plant diversity.

Physical forcing and the dynamics of the pelagic ecosystem in the eastern tropical Pacific: simulations with ENSO-scale and global-warming climate drivers

2003 ◽  
Vol 60 (9) ◽  
pp. 1161-1175 ◽  
Author(s):  
George M Watters ◽  
Robert J Olson ◽  
Robert C Francis ◽  
Paul C Fiedler ◽  
Jeffrey J Polovina ◽  
...  
Keyword(s):  
Global Warming ◽  
Phytoplankton Biomass ◽  
Southern Oscillation ◽  
Tropical Pacific ◽  
Trophic Levels ◽  
Eastern Tropical Pacific ◽  
Ecosystem Models ◽  
Pelagic Ecosystem ◽  
Physical Forcing ◽  
Physical Effects

We used a model of the pelagic ecosystem in the eastern tropical Pacific Ocean to explore how climate variation at El Niño – Southern Oscillation (ENSO) scales might affect animals at middle and upper trophic levels. We developed two physical-forcing scenarios: (1) physical effects on phytoplankton biomass and (2) simultaneous physical effects on phytoplankton biomass and predator recruitment. We simulated the effects of climate-anomaly pulses, climate cycles, and global warming. Pulses caused oscillations to propagate through the ecosystem; cycles affected the shapes of these oscillations; and warming caused trends. We concluded that biomass trajectories of single populations at middle and upper trophic levels cannot be used to detect bottom-up effects, that direct physical effects on predator recruitment can be the dominant source of interannual variability in pelagic ecosystems, that such direct effects may dampen top-down control by fisheries, and that predictions about the effects of climate change may be misleading if fishing mortality is not considered. Predictions from ecosystem models are sensitive to the relative strengths of indirect and direct physical effects on middle and upper trophic levels.

scholarly journals Increase in Air Temperature in The Region of South Sumatra Province as the Indicator of Global Warming and the Effect on Transpiration of Lansium domesticum Corr.

2019 ◽  
Author(s):  
Ari Sugiarto ◽  
Hanifa Marisa ◽  
Sarno
Keyword(s):  
Global Warming ◽  
Air Temperature ◽  
Transpiration Rate ◽  
Temperature Increase ◽  
Secondary Data ◽  
Temperature Data ◽  
Randomized Design ◽  
Maximum Air Temperature ◽  
Lansium Domesticum ◽  
Minimum Air Temperature

Abstract Global warming is one of biggest problems faced in the 21st century. One of the impacts of global warming is that it can affect the transpiration rate of plants that °Ccur. This study purpose to see how much increase in air temperature that occurred in the region of South Sumatra Province and to know the effect of increase in ari temperature in the region of South Sumatra Province on transpiration rate of Lansium domesticum Corr. This study used a complete randomized design with 9 treatments (22.9 °C, 23.6 °C, 24.6 °C, 26.3 °C, 27 °C, 27.8 °C, 31.7 °C, 32.5 °C, and 32.9 °C) and 3 replications. Air temperature data as secondary data obtained from the Meteorology, Climatology and Geophysics Agency (MCGA) Palembang Climatology Station in South Sumatra Province. The measurement of transpiration rate is done by modified potometer method with additional glass box. The data obtained are presented in the form of tables and graphs. Transpiration rate (mm3/g plant/hour) at temperture 22.9 °C = 4.37, 23.6 °C = 7.03, 24.6 °C = 8.03, 26.3 °C = 10.11, 27 °C = 13.13, 27.8 °C = 17.87, 31.7 °C = 23.21, 32.5 °C= 25.45 and 32.9 °C= 27.24. At the minimum air temperature in the region of South Sumatra Province there is increase in air temperature of 1.5 °C, average daily air temperature increase 1.3 °C and maximum air temperature increase 1.2 °C.

scholarly journals Neotyphodium impacts on soil nematode communities: rhizosphere- and litter-mediated interactions

2007 ◽  
Vol 13 ◽  
pp. 107-110
Author(s):  
M. Omacini ◽  
E.J. Chaneton ◽  
C.M. Ghersa
Keyword(s):  
Plant Traits ◽  
Lolium Multiflorum ◽  
Fungal Endophytes ◽  
Patch Dynamics ◽  
Trophic Levels ◽  
Soil Nematode ◽  
Patch Occupancy ◽  
Nematode Communities ◽  
Endophyte Infection ◽  
Soil Nematode Communities

There is a growing recognition that endophyte effects on host plant traits may be propagated through food chains. We studied Neotyphodium occultans effects on soil nematode communities mediated by current and past patch occupancy by endophyteinfected Lolium multiflorum populations. A microcosm experiment was performed to evaluate whether abundance and diversity of nematodes at different trophic levels were affected by endophyte infection through rhizosphere-mediated or littermediated effects. We found that presence of endophyte-infected plants and their aerial litter both triggered a bottom-up trophic cascade enhancing the abundance of herbivorous and predaceous nematode taxa. Endophyte infection also increased overall nematode richness, mostly through changes induced at the highest trophic level in this soil food web. Our results suggest that fungal endophytes can modify the linkages between aboveand belowground community compartments, with potential consequences on plant patch dynamics. Keywords: soil food webs, Lolium multiflorum, Neotyphodium occultans, plant-soil feedback, after-life effects, indirect interactions, trophic cascades

scholarly journals Recent natural variability in global warming weakened phenological mismatch and selection on seasonal timing in great tits ( Parus major )

2021 ◽  
Vol 288 (1963) ◽  
Author(s):  
Marcel E. Visser ◽  
Melanie Lindner ◽  
Phillip Gienapp ◽  
Matthew C. Long ◽  
Stephanie Jenouvrier
Keyword(s):  
Climate Change ◽  
Global Warming ◽  
Climate Variability ◽  
Parus Major ◽  
Great Tit ◽  
Trophic Levels ◽  
Natural Climate Variability ◽  
Seasonal Timing ◽  
Phenological Mismatch ◽  
Natural Climate

Climate change has led to phenological shifts in many species, but with large variation in magnitude among species and trophic levels. The poster child example of the resulting phenological mismatches between the phenology of predators and their prey is the great tit ( Parus major ), where this mismatch led to directional selection for earlier seasonal breeding. Natural climate variability can obscure the impacts of climate change over certain periods, weakening phenological mismatching and selection. Here, we show that selection on seasonal timing indeed weakened significantly over the past two decades as increases in late spring temperatures have slowed down. Consequently, there has been no further advancement in the date of peak caterpillar food abundance, while great tit phenology has continued to advance, thereby weakening the phenological mismatch. We thus show that the relationships between temperature, phenologies of prey and predator, and selection on predator phenology are robust, also in times of a slowdown of warming. Using projected temperatures from a large ensemble of climate simulations that take natural climate variability into account, we show that prey phenology is again projected to advance faster than great tit phenology in the coming decades, and therefore that long-term global warming will intensify phenological mismatches.

scholarly journals Pacific variability reconciles observed and modelled global mean temperature increase since 1950

2020 ◽  
Author(s):  
Martin B. Stolpe ◽  
Kevin Cowtan ◽  
Iselin Medhaug ◽  
Reto Knutti
Keyword(s):  
Global Warming ◽  
Temperature Change ◽  
Temperature Increase ◽  
Global Temperature ◽  
Global Mean Temperature ◽  
Mean Temperature ◽  
The Pacific ◽  
Global Warming Hiatus ◽  
Warming Hiatus ◽  
Global Mean

Abstract Global mean temperature change simulated by climate models deviates from the observed temperature increase during decadal-scale periods in the past. In particular, warming during the ‘global warming hiatus’ in the early twenty-first century appears overestimated in CMIP5 and CMIP6 multi-model means. We examine the role of equatorial Pacific variability in these divergences since 1950 by comparing 18 studies that quantify the Pacific contribution to the ‘hiatus’ and earlier periods and by investigating the reasons for differing results. During the ‘global warming hiatus’ from 1992 to 2012, the estimated contributions differ by a factor of five, with multiple linear regression approaches generally indicating a smaller contribution of Pacific variability to global temperature than climate model experiments where the simulated tropical Pacific sea surface temperature (SST) or wind stress anomalies are nudged towards observations. These so-called pacemaker experiments suggest that the ‘hiatus’ is fully explained and possibly over-explained by Pacific variability. Most of the spread across the studies can be attributed to two factors: neglecting the forced signal in tropical Pacific SST, which is often the case in multiple regression studies but not in pacemaker experiments, underestimates the Pacific contribution to global temperature change by a factor of two during the ‘hiatus’; the sensitivity with which the global temperature responds to Pacific variability varies by a factor of two between models on a decadal time scale, questioning the robustness of single model pacemaker experiments. Once we have accounted for these factors, the CMIP5 mean warming adjusted for Pacific variability reproduces the observed annual global mean temperature closely, with a correlation coefficient of 0.985 from 1950 to 2018. The CMIP6 ensemble performs less favourably but improves if the models with the highest transient climate response are omitted from the ensemble mean.

Scenarios of Global Warming and its Proposed Worldwide Action Plan

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Bharat Raj Singh ◽  
Onkar Singh
Keyword(s):  
Global Warming ◽  
Power Plants ◽  
Fossil Fuel ◽  
Action Plan ◽  
Tidal Energy ◽  
High Rate ◽  
Initial Growth ◽  
Peak Oil ◽  
Vehicular Pollution ◽  
New Formula

Global warming in today's scenario is threat to the survival of mankind. In 1956, Marion King Hubert, an US based Chief consultant and oil geologist predicted that if oil is consumed with high rate, US oil production may peak in 1970 and thereafter it will decline. He also described that other countries may attain peak oil day within 20-30 years and many more may suffer with oil crises within 40 years, when oil wells are going to dry. He illustrated the projection with a bell shaped Hubert Curve based on the availability and its consumptions of the fossil fuel. Large fields are discovered first, small ones later. After exploration and initial growth in output, production plateaus and eventually declines to zero. It is known facts that crude oil, coal and gas are the main resources for world energy supply. The size of fossil fuel reserves and the dilemma that when non-renewable energy will be diminished, is a fundamental and doubtful question that needs to be answered. A new formula for calculating, when fossil fuel reserves are likely to be depleted, is presented along with an econometrics model to demonstrate the relationship between fossil fuel reserves and some main variables. The new formula is modified from the Klass model and thus assumes a continuous compound rate and computes fossil fuel reserve depletion times for oil, coal and gas of approximately 35, 107 and 37 years, respectively. This means that coal reserves are available up to 2112, and will be the only fossil fuel remaining after 2042. In India, vehicular pollution is estimated to have increased eight times over the last two decades. This source alone is estimated to contribute about 70 per cent to the total air pollution. With 243.3 million tons of carbon released from the consumption and combustion of fossil fuels in 1999, India is ranked fifth in the world behind the U.S., China, Russia and Japan. India's contribution to world carbon emissions is expected to increase in the coming years due to the rapid pace of urbanization, shift from non-commercial to commercial fuels, increased vehicular usage and continued use of older and more inefficient coal-fired and fuel power-plants. Thus, peak oil year may be the turning point for mankind which in turn led to the end of 100 year of easy growth, if self-sufficiently and sustainability of energy is not maintained on priority. It may end up a better. This paper describes the worldwide efforts being made to explore non-conventional energy resources such as: solar energy, wind energy, bio-mass and bio-gas, hydrogen, bio-diesel which may help for the sustainable fossil fuel reserves and reduce the tail pipe emission and other pollutants like: CO2, NOX etc.. Also an emphasis is also suggested for the storage of energy such as; battery, flywheel, capacitor devices and storage of air by compressing the air from natural energy sources like: solar, wind and or muscular power. These resources are available in plenty and free of cost and could maintain energy sustainability in 21st century. The tidal energy available in the sea and energy created on account extreme climatic conditions like: storms, tsunami, hurricanes etc. can also be captured and utilized in due course of time if proper diversion and storages are created. This may also definitely leads to environmentally and ecologically better future.

scholarly journals Estimating the near-surface permafrost-carbon feedback on global warming

2012 ◽  
Vol 9 (2) ◽  
pp. 649-665 ◽  
Author(s):  
T. Schneider von Deimling ◽  
M. Meinshausen ◽  
A. Levermann ◽  
V. Huber ◽  
K. Frieler ◽  
...  
Keyword(s):  
Global Warming ◽  
Carbon Cycle ◽  
Soil Carbon ◽  
Temperature Increase ◽  
Climate Model ◽  
Soil Layer ◽  
Permafrost Degradation ◽  
Near Surface ◽  
Uncertainty Range ◽  
Permafrost Thaw

Abstract. Thawing of permafrost and the associated release of carbon constitutes a positive feedback in the climate system, elevating the effect of anthropogenic GHG emissions on global-mean temperatures. Multiple factors have hindered the quantification of this feedback, which was not included in climate carbon-cycle models which participated in recent model intercomparisons (such as the Coupled Carbon Cycle Climate Model Intercomparison Project – C4MIP) . There are considerable uncertainties in the rate and extent of permafrost thaw, the hydrological and vegetation response to permafrost thaw, the decomposition timescales of freshly thawed organic material, the proportion of soil carbon that might be emitted as carbon dioxide via aerobic decomposition or as methane via anaerobic decomposition, and in the magnitude of the high latitude amplification of global warming that will drive permafrost degradation. Additionally, there are extensive and poorly characterized regional heterogeneities in soil properties, carbon content, and hydrology. Here, we couple a new permafrost module to a reduced complexity carbon-cycle climate model, which allows us to perform a large ensemble of simulations. The ensemble is designed to span the uncertainties listed above and thereby the results provide an estimate of the potential strength of the feedback from newly thawed permafrost carbon. For the high CO2 concentration scenario (RCP8.5), 33–114 GtC (giga tons of Carbon) are released by 2100 (68 % uncertainty range). This leads to an additional warming of 0.04–0.23 °C. Though projected 21st century permafrost carbon emissions are relatively modest, ongoing permafrost thaw and slow but steady soil carbon decomposition means that, by 2300, about half of the potentially vulnerable permafrost carbon stock in the upper 3 m of soil layer (600–1000 GtC) could be released as CO2, with an extra 1–4 % being released as methane. Our results also suggest that mitigation action in line with the lower scenario RCP3-PD could contain Arctic temperature increase sufficiently that thawing of the permafrost area is limited to 9–23 % and the permafrost-carbon induced temperature increase does not exceed 0.04–0.16 °C by 2300.

Sign in / Sign up

Export Citation Format

Share Document