Oscillographic polarography with rectangular alternating current. IV. Study of capacity phenomena at various rates of change of electrode potential

The investigations to be described in this paper are the outcome of some work by one of the authors on alternating current electrolysis, in which the behaviour of platinum, gold and nickel electrodes, using dilute sulphuric acid and barium hydrate solution as electrolytes, was examined for alternating current with frequencies lying between 25 cycles and 80 cycles per second. Some provisional measurements of the electrode drop were made at that time, but it was felt desirable to examine this feature in greater detail. The apparatus employed for the purpose is shown in fig. 1. The electrolyte was contained in a glass tube EF, 60 cm. long and 4 cm. diameter, provided with a feed tube D. The ends were closed with rubber stoppers, each pierced with two holes, through which passed tubes holding electrodes A and C and an “explorer” B, and a thermometer T. The electrode C was of platinum, and remained unchanged throughout all the experiments.

Download Full-text

Modelling ecosystem adaptation and dangerous rates of global warming

Emerging Topics in Life Sciences ◽

10.1042/etls20180113 ◽

2019 ◽

Vol 3 (2) ◽

pp. 221-231 ◽

Cited By ~ 4

Author(s):

Rebecca Millington ◽

Peter M. Cox ◽

Jonathan R. Moore ◽

Gabriel Yvon-Durocher

Keyword(s):

Climate Change ◽

Global Warming ◽

Diffusion Rate ◽

Individual Species ◽

Genetic Evolution ◽

Rates Of Change ◽

Rapid Climate Change ◽

Warming Climate ◽

Intraspecies Competition ◽

High Trait

Abstract We are in a period of relatively rapid climate change. This poses challenges for individual species and threatens the ecosystem services that humanity relies upon. Temperature is a key stressor. In a warming climate, individual organisms may be able to shift their thermal optima through phenotypic plasticity. However, such plasticity is unlikely to be sufficient over the coming centuries. Resilience to warming will also depend on how fast the distribution of traits that define a species can adapt through other methods, in particular through redistribution of the abundance of variants within the population and through genetic evolution. In this paper, we use a simple theoretical ‘trait diffusion’ model to explore how the resilience of a given species to climate change depends on the initial trait diversity (biodiversity), the trait diffusion rate (mutation rate), and the lifetime of the organism. We estimate theoretical dangerous rates of continuous global warming that would exceed the ability of a species to adapt through trait diffusion, and therefore lead to a collapse in the overall productivity of the species. As the rate of adaptation through intraspecies competition and genetic evolution decreases with species lifetime, we find critical rates of change that also depend fundamentally on lifetime. Dangerous rates of warming vary from 1°C per lifetime (at low trait diffusion rate) to 8°C per lifetime (at high trait diffusion rate). We conclude that rapid climate change is liable to favour short-lived organisms (e.g. microbes) rather than longer-lived organisms (e.g. trees).

Download Full-text