scholarly journals Temperature dependence of coastal wetland ecosystem respiration confounded by tidal activities: a temporal perspective

2013 ◽  
Vol 10 (3) ◽  
pp. 4515-4537 ◽  
Author(s):  
X. Xie ◽  
M.-Q. Zhang ◽  
B. Zhao ◽  
H.-Q. Guo
Keyword(s):  
Time Scales ◽  
Temperature Sensitivity ◽  
Coastal Wetland ◽  
Ecosystem Respiration ◽  
Tidal Effect ◽  
Short Term ◽  
Confounding Effect ◽  
Hydrological Condition ◽  
Term Model

Abstract. Variations of temperature and hydrological conditions result in the fluctuation of ecosystem respiration (ER). Temperature sensitivity is widely used to describe ER-temperature relationship, but hydrological condition with similar dynamics as temperature could cause confounding effect. Many researchers have made comparisons between long-term and short-term models to show the confounding effect. However, how temperature sensitivity is confounded by hydrological condition in different time scales remains unknown. In this study, data from two coastal wetland sites were used. By comparing the variations of temperature and tidal influence at three time scales (monthly, seasonal and half-yearly), we found that: (1) the co-variation of temperature and other environmental factors accounted for the long-term confounding effect, and (2) the small variances of temperature in short time scale explained the short-term confounding effect. As a result of the long-term confounding effect, greater system errors were introduced in long-term model than short-term did. As the temperature sensitivity derived from long-term "ignored" the alternation of main driving factor of ER, temperature influence on ER was overestimated while the tidal influence was underestimated. Tidal activities had great influences on ER when the variances of temperature were small. If short-term model without tidal effect was applied, short-term confounding effect was inevitable. Compared to the long-term model (half-yearly), short-term model (monthly without tidal effect) performed better that helped reduce the long-term confounding effect, and integrating a proper secondary factor like tide would further reduce the short-term confounding effect.

scholarly journals Metabolic plasticity can amplify ecosystem responses to global warming

2021 ◽  
Author(s):  
Rebecca Kordas ◽  
Samraat Pawar ◽  
Guy Woodward ◽  
Eoin O'Gorman
Keyword(s):  
Global Warming ◽  
Body Size ◽  
Predictive Models ◽  
Chronic Exposure ◽  
Ecosystem Respiration ◽  
Short Term ◽  
Ecosystem Responses ◽  
Metabolic Plasticity ◽  
Ecosystem Level

Abstract Organisms have the capacity to alter their physiological response to warming through acclimation or adaptation, but empirical evidence for this metabolic plasticity across species within food webs is lacking, and a generalisable framework does not exist for modelling its ecosystem-level consequences. Here we show that the ability of organisms to raise their metabolic rate following chronic exposure to warming decreases with increasing body size. Chronic exposure to higher temperatures also increases the sensitivity of organisms to short-term warming, irrespective of their body size. A mathematical model parameterised with these findings shows that metabolic plasticity could account for an additional 60% of ecosystem energy flux with just +2 °C of warming. This could explain why ecosystem respiration continues to rise in long-term warming experiments and highlights the need to embed metabolic plasticity in predictive models of global warming impacts on ecosystems.

scholarly journals Short-Term and Long-Term Surface Soil Moisture Memory Time Scales Are Spatially Anticorrelated at Global Scales

2019 ◽  
Vol 20 (6) ◽  
pp. 1165-1182 ◽  
Author(s):  
Kaighin A. McColl ◽  
Qing He ◽  
Hui Lu ◽  
Dara Entekhabi
Keyword(s):  
Soil Moisture ◽  
Time Scales ◽  
Time Scale ◽  
Surface Soil ◽  
Satellite Observations ◽  
Surface Soil Moisture ◽  
Short Term ◽  
Term Memory ◽  
Memory Time

Abstract Land–atmosphere feedbacks occurring on daily to weekly time scales can magnify the intensity and duration of extreme weather events, such as droughts, heat waves, and convective storms. For such feedbacks to occur, the coupled land–atmosphere system must exhibit sufficient memory of soil moisture anomalies associated with the extreme event. The soil moisture autocorrelation e-folding time scale has been used previously to estimate soil moisture memory. However, the theoretical basis for this metric (i.e., that the land water budget is reasonably approximated by a red noise process) does not apply at finer spatial and temporal resolutions relevant to modern satellite observations and models. In this study, two memory time scale metrics are introduced that are relevant to modern satellite observations and models: the “long-term memory” τL and the “short-term memory” τS. Short- and long-term surface soil moisture (SSM) memory time scales are spatially anticorrelated at global scales in both a model and satellite observations, suggesting hot spots of land–atmosphere coupling will be located in different regions, depending on the time scale of the feedback. Furthermore, the spatial anticorrelation between τS and τL demonstrates the importance of characterizing these memory time scales separately, rather than mixing them as in previous studies.

scholarly journals Dependence of coastal wetland ecosystem respiration on temperature and tides: a temporal perspective

2014 ◽  
Vol 11 (3) ◽  
pp. 539-545 ◽  
Author(s):  
X. Xie ◽  
M.-Q. Zhang ◽  
B. Zhao ◽  
H.-Q. Guo
Keyword(s):  
Regression Models ◽  
Coastal Wetland ◽  
Ecosystem Respiration ◽  
Study Data ◽  
Tidal Effect ◽  
Temporal Perspective ◽  
Hydrological Conditions ◽  
Temporal Domain ◽  
Lower Elevation ◽  
Periodic Dynamics

Abstract. Variations in temperature are widely invoked to explain fluctuations in ecosystem respiration (ER), but hydrological conditions also influence ER. Many researchers have observed that aperiodic variations in hydrological conditions affect ER and the associated temperature sensitivity. However, little is known about how periodic hydrological dynamics affect ER and its relationship with temperature on different timescales. In the present study, data from two coastal wetland sites were used to compare the variations in thermal and tidal influences on ER at three timescales (monthly, seasonal, and semiannual), and we found that (1) the influences of tides and temperature on ER varied with time. Especially in summer, the ER exhibited periodic dynamics regulated by tides; (2) in the temporal domain, temperature was dominant at the semiannual and seasonal scales, while the tidal effect was dominant at the monthly scale. In the spatial domain, the relative importance of temperature was greater at higher elevation sites, while tides exerted more influence at lower elevation sites; (3) the monthly model with tidal effect performed best, while regression models at semiannual and seasonal scales generated systematic errors in ER. These results demonstrate that, for coastal wetlands, the application of parameters from regression models based on long-term (seasonal or semiannual) data should be avoided in gap filling, and the effects of tides and elevation should be considered in estimating the carbon budget.

scholarly journals Trends and Persistence of Dry–Wet Conditions in Northeast Brazil

Atmosphere ◽  
2020 ◽  
Vol 11 (10) ◽  
pp. 1134
Author(s):  
Antonio Samuel Alves da Silva ◽  
Moacyr Cunha Filho ◽  
Rômulo Simões Cezar Menezes ◽  
Tatijana Stosic ◽  
Borko Stosic
Keyword(s):  
Time Scales ◽  
Water Resource Management ◽  
Standardized Precipitation Index ◽  
Kendall Test ◽  
Spatially Explicit ◽  
Fluctuation Analysis ◽  
Short Term ◽  
Agricultural Planning ◽  
Detrended Fluctuation

We analyze trend and persistence in Standardized Precipitation Index (SPI) time series derived from monthly rainfall data at 133 gauging stations in Pernambuco state, Brazil, using a suite of complementary methods to address the spatially explicit tendencies, and persistence. SPI was calculated for 1-, 3-, 6-, and 12-month time scales from 1950 to 2012. We use Mann–Kendall test and Sen’s slope to determine sign and magnitude of the trend, and detrended fluctuation analysis (DFA) method to quantify long-term correlations. For all time scales significant negative trends are obtained in the Sertão (deep inland) region, while significant positive trends are found in the Agreste (intermediate inland), and Zona da Mata (coastal) regions. The values of DFA exponents show different scaling behavior for different time scales. For short-term conditions described by SPI-1 the DFA exponent is close to 0.5 indicating weak persistency and low predictability, while for medium-term conditions (SPI-3 and SPI-6) DFA exponents are greater than 0.5 and increase with time scale indicating stronger persistency and higher predictability. For SPI-12 that describes long-term precipitation patterns, the values of DFA exponents for inland regions are around 1, indicating strong persistency, while in the shoreline the value of the DFA exponent is between 1.0 and 1.5, indicating anti-persistent fractional Brownian motion. These results should be useful for agricultural planning and water resource management in the region.

scholarly journals Short term changes in methanol emission and pectin methylesterase activity are not directly affected by light in <i>Lycopersicon esculentum</i>

2011 ◽  
Vol 8 (4) ◽  
pp. 1023-1030 ◽  
Author(s):  
P. Y. Oikawa ◽  
L. Li ◽  
M. P. Timko ◽  
J. E. Mak ◽  
M. T. Lerdau
Keyword(s):  
Time Scales ◽  
Pectin Methylesterase ◽  
Light Activation ◽  
Short Term ◽  
Substrate Limitation ◽  
Emission Models ◽  
Seasonal Time Scale ◽  
Short Time ◽  
Cell Wall Expansion

Abstract. Plants are an important source of atmospheric methanol (MeOH), the second most abundant organic gas after methane. Factors regulating phytogenic MeOH production are not well constrained in current MeOH emission models. Previous studies have indicated that light may have a direct influence on MeOH production. As light is known to regulate cell wall expansion, it was predicted that light would stimulate MeOH production through the pectin methylesterase (PME) pathway. MeOH emissions normalized for stomatal conductance (gs) did not, however, increase with light over short time scales (20–30 min). After experimentally controlling for gs and temperature, no light activation of PME activity or MeOH emission was observed. The results clearly demonstrate that light does not directly influence short-term changes in MeOH production and emission. Our data suggest that substrate limitation may be important in regulating MeOH production over short time scales. Future investigation of the long-term impacts of light on MeOH production may increase understanding of MeOH emission dynamics at the seasonal time scale.

Abstract 039: Comparison of Costs & Outcomes of Dapagliflozin With Dipeptidyl Peptidase-4 Inhibitors Added to Metformin Using a Short-term Cost-effectiveness Model

2017 ◽  
Vol 10 (suppl_3) ◽  
Author(s):  
Abhiroop Chakravarty ◽  
Mohini Rastogi ◽  
Praveen Dhankhar ◽  
Kelly Bell
Keyword(s):  
Cost Effectiveness ◽  
Cost Saving ◽  
Economic Impact ◽  
Costs And Benefits ◽  
Short Term ◽  
End Points ◽  
Dipeptidyl Peptidase 4 ◽  
Term Model ◽  
Dipeptidyl Peptidase 4 Inhibitors

Background: Several long-term models have been developed to compare the economic impact of alternative anti-diabetic treatments. However short-term models, based on actual trial data, might give more accurate results and be preferable over long-term models for estimating costs and benefits in short term. Objective: To assess the economic impact of the antidiabetic drug dapagliflozin (DAPA), a sodium-glucose cotransporter-2 (SGLT-2) inhibitor, and dipeptidyl peptidase-4 inhibitors (DPP-4i) combined with metformin in the treatment of T2D. Methods: A short-term decision-analytic model with one year time horizon was developed using a payer’s perspective for United States (US). Costs and benefits associated with four clinical end points (glycated hemoglobin [HbA1c], body weight, systolic blood pressure (SBP), and risk of hypoglycemia) were evaluated in the analysis. A network meta-analysis was utilized to evaluate the impact of DAPA vs. DPP-4i on these clinical end points. Data for costs and QALYs associated with a per unit change in these clinical end points was taken from published literature. Drug prices were taken from annual wholesale price list. All costs were inflation-adjusted to 2016 costs using the medical care component of the consumer price index. Total costs (medical and drug), total QALYs, and incremental cost effectiveness ratios (ICERs) were estimated. Sensitivity analyses were performed as well. Results from the short-term model were compared with long term models published for these treatments. Results: Total annual medical cost for DAPA was $1,119 less than that for DPP-4i, with the difference mainly attributable to cost associated with weight change ($860). Treatment with DAPA resulted in an average QALY gain of 0.0587 per treated patient compared to DPP-4i. DAPA was cost-saving when compared to DPP-4i. Among all the four clinical end points, change in weight had the greatest impact on total annual costs and ICERs. Probabilistic sensitivity analysis demonstrated that total annual cost for DAPA was less than that for DPP-4i in more than 97% of simulations and DAPA had a 97% probability of being cost-saving compared with DPP-4i. Results from the short-term model were similar to published long term models. Conclusions: Our analysis showed that DAPA was cost saving when compared with DPP-4i in the US setting. Furthermore, the results suggest that among the four composite clinical endpoints, change in weight had greater impact on cost-effectiveness results. In addition, our short-term model provides results similar to published long term models.

Climate Change Impacts on a Mediterranean Coastal Wetland due to Sea Level Rise (L’Albufera de Valencia, Spain)

2021 ◽  
Author(s):  
Clara E Estrela Segrelles ◽  
Miguel Ángel Pérez Martín ◽  
Gabriel Gómez Martínez
Keyword(s):  
Climate Change ◽  
Sea Level Rise ◽  
Sea Level ◽  
Coastal Wetlands ◽  
Coastal Wetland ◽  
Water Volume ◽  
Lake Ecosystem ◽  
Lake Levels ◽  
Short Term

&lt;p&gt;Sea level rise produced by climate change severely affects coastal ecosystems. The increase in the area below sea level facilitates the penetration of the marine wedge and causes an increase in soil salinity. Coastal wetlands are areas of great ecological importance due to the richness of flora and fauna that inhabit them. A change in salinity conditions could lead to a reduction or loss of habitat for the wetland biota. Based on RCP4.5 and RCP8.5 CMIP5 multimodel scenarios, in the Western Mediterranean coast, the sea level will rise 0.16 m in the short term (2026 - 2045) and 0.79 m in 2100. Also, high-end scenarios indicate that sea level will rise between 1.35 m and 1.92 m in the long term.&lt;/p&gt;&lt;p&gt;A sea level rise analysis has been developed in the coastal wetlands of J&amp;#250;car River Basin District (JRBD). The results show that coastal wetlands are the mainly area affected in the JRBD, so the 90% of the area under the sea level are wetlands. L&amp;#8217;Albufera de Valencia is the main wetland in this basin and, also the main wetland affected. It is an anthropized humid zone, regulated by users through gates to preserve the adequate water level for agricultural and environmental purposes such as rice cultivation around the lake and bird habitats conservation, especially in winter. The outcome of the study shows a significative increase in the area below the sea from 507 ha and 4.2 hm&lt;sup&gt;3&lt;/sup&gt; of water volume at present to 3,244 ha that represents 42.6 hm&lt;sup&gt;3&lt;/sup&gt; of water volume in the short term. In the long term, the area below the sea is 7,253 ha which means 118.4 hm&lt;sup&gt;3&lt;/sup&gt; of water volume in the percentile 50 scenario and, in the worst extreme scenario, it is 13,896 ha that represents 289.7 hm&lt;sup&gt;3&lt;/sup&gt; of water volume. This leads to a redefinition of the lake management levels as a climate change adaptation measure to prevent the lake salinization and severe impacts in the lake ecosystem. L&amp;#8217;Albufera lake levels need to be increased in the next years to avoid the sea water penetration, related to the sea level rise. Thus, in the short term the lake levels must be increased around 0.16 m and, in the long term, L&amp;#8217;Albufera levels must be increased around 0.8 m.&lt;/p&gt;

scholarly journals Onshore–offshore gradient in metacommunity turnover emerges only over macroevolutionary time-scales

2014 ◽  
Vol 281 (1795) ◽  
pp. 20141533 ◽  
Author(s):  
Adam Tomašových ◽  
Stefano Dominici ◽  
Martin Zuschin ◽  
Didier Merle
Keyword(s):  
Time Scales ◽  
Thermal Gradients ◽  
Short Term ◽  
Northeast Atlantic ◽  
Atlantic Province ◽  
Temporal Turnover ◽  
Warm Temperate ◽  
Molluscan Species

Invertebrate lineages tend to originate and become extinct at a higher rate in onshore than in offshore habitats over long temporal durations (more than 10 Myr), but it remains unclear whether this pattern scales down to durations of stages (less than 5 Myr) or even sequences (less than 0.5 Myr). We assess whether onshore–offshore gradients in long-term turnover between the tropical Eocene and the warm-temperate Plio-Pleistocene can be extrapolated from gradients in short-term turnover, using abundances of molluscan species from bulk samples in the northeast Atlantic Province. We find that temporal turnover of metacommunities does not significantly decline with depth over short durations (less than 5 Myr), but significantly declines with depth between the Eocene and Plio-Pleistocene (approx. 50 Myr). This decline is determined by a higher onshore extinction of Eocene genera and families, by a higher onshore variability in abundances of genera and families, and by an onshore expansion of genera and families that were frequent offshore in the Eocene. Onshore–offshore decline in turnover thus emerges only over long temporal durations. We suggest that this emergence is triggered by abrupt and spatially extensive climatic or oceanographic perturbations that occurred between the Eocene and Plio-Pleistocene. Plio-Pleistocene metacommunities show a high proportion of bathymetric generalists, in contrast to Eocene metacommunities. Accordingly, the net cooling and weaker thermal gradients may have allowed offshore specialists to expand into onshore habitats and maintain their presence in offshore habitats.

High-resolution records of the response of coastal wetland systems to long-term and short-term sea-level variability

2009 ◽  
Vol 84 (4) ◽  
pp. 493-508 ◽  
Author(s):  
Alexander S. Kolker ◽  
Steven L. Goodbred ◽  
Sultan Hameed ◽  
J. Kirk Cochran
Keyword(s):  
High Resolution ◽  
Sea Level ◽  
Coastal Wetland ◽  
Short Term ◽  
Sea Level Variability

scholarly journals Psychological Momentum During and Across Sports Matches: Evidence for Interconnected Time Scales

2016 ◽  
Vol 38 (1) ◽  
pp. 82-92 ◽  
Author(s):  
Ruud J. R. Den Hartigh ◽  
Paul L. C. Van Geert ◽  
Nico W. Van Yperen ◽  
Ralf F. A. Cox ◽  
Christophe Gernigon
Keyword(s):  
Dynamical Systems ◽  
Time Scales ◽  
Self Efficacy ◽  
Short Term ◽  
The Third ◽  
Psychological Momentum ◽  
Rowing Ergometer ◽  
Competitive Athletes ◽  
Dynamical Nature

This study on psychological momentum (PM) in sports provides the first experimental test of an interconnection between short-term PM (during a match) and long-term PM (across a series of matches). Twenty-two competitive athletes were striving to win a prize during a rowing-ergometer tournament, consisting of manipulated races. As hypothesized, athletes who had developed long-term positive PM after two successful races were less sensitive to a negative momentum scenario in the third race, compared with athletes who had developed long-term negative PM after two unsuccessful races. More specifically, the exerted efforts, perceptions of momentum, and self-efficacy were higher for participants who had developed long-term positive PM, and their perceptions of momentum and self-efficacy decreased less rapidly. These results illustrate a typical complex dynamical systems property, namely interconnected time scales, and provide deeper insights into the dynamical nature of PM.

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