What is the optimum temperature for life on Earth?

Have you ever wondered what it is? temperature optimal for life on Earth? for people, 20°C is pleasant. If it’s hotter, we will work less efficiently because it takes energy to release heat.

We know that many species can live in temperatures much colder or warmer than humans. However, our systematic review of published research found that the temperature ranges of animals, plants and microbes living in air and water overlap at 20°C. Could this be a coincidence?

For all species, the relationship with temperature is an asymmetric bell-shaped curve. This means that biological processes increase according to temperaturethey peak and then drop rapidly when it gets too hot.

Recently, a New Zealand research group noted that the no Marine species It did not peak at the equator as is commonly believed. More like a number reducedwith peaks in the subtropics.

Subsequent studies have shown that this decline has been deepening since the last ice age, about 20,000 years ago. And thanks to this, it deepens faster global warming oceans. When comparing the number of species with the average annual temperature, there was a decrease above 20°C. Second chance?

Research in Tasmania modeled the growth rates of microbes and multicellular organisms and found that the most stable temperature for their biological processes was also 20°C. This “Corkrey model” was based on other studies showing that 20°C was the most stable temperature for biological molecules. Third chance?

We teamed up with colleagues from Canada, Scotland, Germany, Hong Kong and Taiwan to look for general patterns in how temperature affects life. To our surprise, everywhere we looked we found that in fact 20°C is the base temperature for many measures of biodiversity, not just marine species.

Examples show that temperatures above about 20 °C result in reductions in several crucial measures, such as the tolerance of marine and freshwater species to low oxygen levels; productivity of pelagic (living in open water) and benthic (living on the sea floor) seaweeds and predation rates of baitfish; Global species richness of pelagic fish, plankton, benthic invertebrates and fossil molluscs; and genetic diversity.

There was also a increase in extinction in the fossil record when temperatures exceeded 20°C.

Globally, the temperature range in which reef fish and invertebrates live is narrower for species whose geographic distribution is concentrated around 20 °C. The same effect is observed in microbes.

Although many species have evolved to live in higher and lower temperatures, most live at 20°C. In addition, extinctions in the fossil record (including sponges, lamp shells, molluscs, sea mats (kelp), starfish and urchins, worms and crustaceans) were lower than 20 °C.

As species evolve to live at temperatures above and below 20°C, their the thermal niche widens. This means that most can still live at 20°C even if they live in warmer or colder places.

Corkrey’s mathematical model predicts that the thermal amplitude should be minimized and that biological processes would be more stable and efficient at 20 °C. This, in turn, should maximize species richness in all domains of life, from bacteria to multicellular plants and animals. Therefore, the model provides a theoretical explanation for this “Effect of 20°C’.

That life seems to be centered around 20°C suggests limitations foundations that threaten the ability of tropical species to adapt to higher temperatures.

As long as species are able to change their ranges to adapt to global warming, the 20°C effect means that there will be local increases in species richness up to an annual mean of 20°C. over that, wealth will decrease. This means that many marine species that can adapt to global warming by changing their geographic distribution are unlikely to become extinct as a result of climate change.

However, it is possible that terrestrial species they cannot change their geographical distribution so easily thanks to landscapes modified by cities, agriculture and other human infrastructure.

The 20°C effect is the simplest explanation for the above phenomena, which include: trends in species richness and genetic diversity with temperature; extinction rates in the fossil record; biological productivity; optimal growth rate; and the rate of marine predation. Despite the complexity of multicellular species, it is remarkable that thermal efficiency at the cellular level is reflected in these other aspects of biodiversity.

The exact reason why it’s 20°C basic and energetically efficient for cellular processes may be due to the molecular properties of cell-associated water. These properties may also be why ~42°C appears to be the absolute limit for most species.

Greater awareness of this 20°C effect may lead to new insights into how temperature controls ecosystem processes, species abundance and distribution, and evolution of life.

*Marcos John Costello is Professor in the School of Biosciences and Aquaculture, Northern University, and co-authored this article with Ross Corkrey, Senior Research Associate in Biostatistics, University of Tasmania. This article was originally published in Conversation.