Acidic loving microbes can increase understanding of past climates, The availability of food and energy causes physical changes in acid-loving microorganisms that are used to study the history of the Earth’s climate.
These are the results of a study by Dartmouth College.
The finding that factors other than temperature can affect unicellular archeological membrane membranes adds to the complexity of paleoclimatic studies that traditionally use fossil microbial remains to reconstruct past climates. Acidic loving microbes can increase understanding of past climates.
Archaea are one of the three main areas of life with bacteria and eukarya, a domain that includes animals and plants.
Biomarkers, like fat molecules that build cell membranes in our body, can be powerful environmental writers that can last for billions of years.
The motivation behind this research is to better explain how archaea react to all major types of stress in their environment and how they record this stress in fat molecules that survive during geological time. Acidic loving microbes can increase understanding of past climates.
Cell membranes consist of lipids that protect cells from changes in their environment, such as temperature, acidity and food availability.
Fluctuations in external conditions can cause organisms to change their membrane structure to support survival.
Ordinary archaea that live in the ocean react to changes in temperature and change the “packaging efficiency” of their lipid membranes. The proximity of this adjacent packing can be adjusted by adjusting the number of ring molecules in the lipids.
Counting the number of rings in this preserved lipid allows researchers to use ancient microorganism deposits to determine past ocean temperatures.
While most archeological studies focus on species that live in lakes and oceans, Dartmouth researchers have studied heat and acid termasidophils which initially developed into hot springs and thrive in some of the most extreme environments on earth.
Instead of studying how microbes respond to temperature changes, the research team focused on the effects of different food and energy availability. Acidic loving microbes can increase understanding of past climates.
The idea that access to food stimulates membrane changes recently has been suggested in low-temperature archea that live in the oceans.
This is the first evidence that this effect is seen even with acidic high temperature germs.
The Dartmouth Laboratory uses a thermoacidophile called Sulfolobus acidocaldarius for experimentation because it is evolutionarily closely related to archaea in the ocean and common in extreme environments for most of the past, and gives researchers insight into past conditions on the planet.
The fast growth of microbes also makes it useful in laboratory experiments.
The researchers placed the body in a bioreactor with a constant combustion temperature of 80 degrees Celsius and a pH value close to the battery acid.
By controlling the amount of sugar available to microbes, the team showed that food concentration is directly related to the number of rings in the membrane.
This bioreactor-based approach is unique because we can completely isolate the effects of sugar limitation on these germs, “said Alice Zhou, who was the first author of this study as a PhD student at Dartmouth.
This differs from most microbiological experiments carried out in closed system culture, where several variables such as solution chemistry and population size change over time and falsify the results.
This study aims to assist geologists and climatologists in their efforts to improve records of past sea surface temperatures and to combine portraits of Earth’s past climate.
When interpreting geological data, it is important to be as careful as possible. It is very rare that there is only one factor in the game.
According to the research team, existing proxies, which use archaeal membrane data to determine past temperatures (TEX86), are accurate in most sea surface environments.
However, there are important anomalies in locations such as polar regions where the temperature predicted by TEX86 may not match actual measurements.
Given the fact that the current TEX86 proxy can produce inconclusive results in certain circumstances, we hope that research can help improve climate records if differences occur.
Research has shown that energy limitation is a common phenomenon that causes these microbes to change the type and structure of the lipids produced.
This study shows that the response to energy-limiting lipids for archaea can be universal and must therefore always be taken into consideration when evaluating what lipids originating from old sediments for the research community.