scholarly journals Dark survival in a warming world

2013 ◽  
Vol 280 (1755) ◽  
pp. 20122909 ◽  
Author(s):  
A. McMinn ◽  
A. Martin

Most algae regularly experience periods of darkness ranging from a few hours to a few days. During this time, they are unable to photosynthesize, and so must consume stored energy products. However, some organisms such as polar algae and some microalgal cysts and spores are exposed to darkness for months to years, and these must use alternative strategies to survive. Some taxa, such as dinoflagellates, form cysts and become dormant. Others use physiological methods or adopt mixotrophy. The longest documented survival of more than a century was for dinoflagellates buried in sediments in a Norwegian fjord. Seasonal changes in daylight hours are naturally unaffected by climate change. This means that polar microalgae will in the future need to survive the same period of seasonal darkness but at higher temperatures, and this will require a greater drawdown of stored energy. Recent experimental work has shown that both Arctic and Antarctic phytoplankton are able to survive increases of up to 6°C in the dark.

2018 ◽  
Vol 1 (36) ◽  
pp. 2
Author(s):  
Barbara Zanuttigh ◽  
Sara Mizar Formentin ◽  
Giuseppina Palma ◽  
Maria Gabriella Gaeta ◽  
Massimo Guerrero ◽  
...  

The effects of climate change with increased sea level and intensity of the extreme storms leads to an increase of the loads and of the expected overtopping at existing seawalls. The inclusion of bull-noses in the design of seawalls seems to significantly reduce the wave overtopping discharge q and may be an effective solution to face climate change while limiting the increase of the seawalls height and the costs. The experimental work by Van Doorslaer et al. (2015), VD hereinafter, is the only systematic study available so far about the effects of bull-noses on the reduction of q. They developed a number of formulae, adopted then by EurOtop (2016), in case the seawall is placed on a dike slope or at the end of a promenade. The work we are proposing here starts from these findings, to analyze a different case: dikes with a finite crest width and an inshore crown wall with and without a bull-nose. The aim is to verify whether the formulae developed by VD can still be used or require some modifications to complete the existing design formulae.


2018 ◽  
Author(s):  
Amy Hurford ◽  
Christina A. Cobbold ◽  
Péter K. Molnár

AbstractPopulation growth metrics such asR0are usually asymmetric functions of temperature, with cold-skewed curves arising when the positive effects of a temperature increase outweigh the negative effects, and warm-skewed curves arising in the opposite case. Classically, cold-skewed curves are interpreted as more beneficial to a species under climate warming, because cold-skewness implies increased population growth over a larger proportion of the species’ fundamental thermal niche than warm-skewness. However, inference based on the shape of the fitness curve alone, and without considering the synergistic effects of net reproduction, density, and dispersal may yield an incomplete understanding of climate change impacts. We formulate a moving-habitat integrodifference equation model to evaluate how fitness curve skewness affects species’ range size and abundance during climate warming. In contrast to classic interpretations, we find that climate warming adversely affects populations with cold-skewed fitness curves, positively affects populations with warm-skewed curves and has relatively little or mixed effects on populations with symmetric curves. Our results highlight the synergistic effects of fitness curve skewness, spatially heterogeneous densities, and dispersal in climate change impact analyses, and that the common approach of mapping changes only inR0may be misleading.


Parasitology ◽  
1965 ◽  
Vol 55 (3) ◽  
pp. 439-451 ◽  
Author(s):  
C. R. Keneedy

Recent experimental work has indicated that species of Archigetes are capable of infecting and maturing in fishes in addition to tubificids.The genus Archigetes is re-defined on the basis of morphological and biological characters, with particular emphasis on recent life history studies. All species capable of neotenic development have been re-united in a single genus.A description of all species of Archigetes together with a key for their identification are included. New synonomies are discussed.The relationship of Archigetes to other genera of the family is briefly considered, and it is concluded that it forms the terminal stage in a series showing the attainment of neotenic development.I wish to thank Professor R. J. Pumphrey in whose Department the work was carried out, and Dr J. C. Chubb for advice and help in the preparation of this manuscript. I am also grateful to Professor K. Berg and Dr R. L. Calentine for the loan of specimens. The work was carried out during the tenure of a Nature Conservancy Research Studentship.


2020 ◽  
pp. 189-214
Author(s):  
Carson T. Schütze

This chapter addresses how linguists’ empirical (syntactic) claims should be tested with non-linguists. Recent experimental work attempts to measure rates of convergence between data presented in journal articles and the results of large surveys. Three follow-up experiments to one such study are presented. It is argued that the original method may underestimate the true rate of convergence because it leaves considerable room for naïve subjects to give ratings that do not reflect their true acceptability judgments of the relevant structures. To understand what can go wrong, the experiments were conducted in two parts. The first part had visually presented sentences rated on a computer, replicating previous work. The second part was an interview where the experimenter asked the participants about the ratings they gave to particular items, in order to determine what interpretation or parse they had assigned, whether they had missed any critical words, and so on.


Diversity ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 257
Author(s):  
Joel Ralston ◽  
William V. DeLuca

Many North American boreal forest birds reach the southern periphery of their distribution in the montane spruce–fir forests of northeastern United States and the barren coastal forests of Maritime Canada. Because the southern periphery may be the first to be impacted by warming climates, these populations provide a unique opportunity to examine several factors that will influence the conservation of this threatened group under climate change. We discuss recent research on boreal birds in Northeastern US and in Maritime Canada related to genetic diversity, population trends in abundance, distributional shifts in response to climate change, community composition, and threats from shifting nest predators. We discuss how results from these studies may inform the conservation of boreal birds in a warming world as well as open questions that need addressing.


2019 ◽  
Vol 286 (1908) ◽  
pp. 20191157 ◽  
Author(s):  
Amy Hurford ◽  
Christina A. Cobbold ◽  
Péter K. Molnár

Population growth metrics such as R 0 are usually asymmetric functions of temperature, with cold-skewed curves arising when the positive effects of a temperature increase outweigh the negative effects, and warm-skewed curves arising in the opposite case. Classically, cold-skewed curves are interpreted as more beneficial to a species under climate warming, because cold-skewness implies increased population growth over a larger proportion of the species's fundamental thermal niche than warm-skewness. However, inference based on the shape of the fitness curve alone, and without considering the synergistic effects of net reproduction, density and dispersal, may yield an incomplete understanding of climate change impacts. We formulate a moving-habitat integrodifference equation model to evaluate how fitness curve skewness affects species’ range size and abundance during climate warming. In contrast to classic interpretations, we find that climate warming adversely affects populations with cold-skewed fitness curves, positively affects populations with warm-skewed curves and has relatively little or mixed effects on populations with symmetric curves. Our results highlight the synergistic effects of fitness curve skewness, spatially heterogeneous densities and dispersal in climate change impact analyses, and that the common approach of mapping changes only in R 0 may be misleading.


2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Claudia F. Nisa ◽  
Jocelyn J. Bélanger ◽  
Birga M. Schumpe ◽  
Daiane G. Faller

Abstract No consensus exists regarding which are the most effective mechanisms to promote household action on climate change. We present a meta-analysis of randomised controlled trials comprising 3,092,678 observations, which estimates the effects of behavioural interventions holding other factors constant. Here we show that behavioural interventions promote climate change mitigation to a very small degree while the intervention lasts (d = −0.093 95% CI −0.160, −0.055), with no evidence of sustained positive effects once the intervention ends. With the exception of recycling, most household mitigation behaviours show a low behavioural plasticity. The intervention with the highest average effect size is choice architecture (nudges) but this strategy has been tested in a limited number of behaviours. Our results do not imply behavioural interventions are less effective than alternative strategies such as financial incentives or regulations, nor exclude the possibility that behavioural interventions could have stronger effects when used in combination with alternative strategies.


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