Photo credit: www.sciencedaily.com

Microorganisms Thrive in Extreme Conditions at Hydrothermal Vents

Microorganisms play a crucial role in the global carbon cycle, employing a range of techniques for carbon fixation. Recent research conducted by teams from Bremen, Germany, and Taiwan has focused on the unique strategies adopted by these organisms in the harsh environments of hydrothermal vents off the coast of Kueishantao, Taiwan. This study, led by Joely Maak from the MARUM — Center for Marine Environmental Sciences at the University of Bremen, has been published in the journal Biogeosciences.

Extrema can be found even in coastal marine environments, particularly in areas influenced by hydrothermal systems. These systems, which transport materials from the Earth’s crust to the surface, often serve as the primary energy source in deeper ocean regions where photosynthesis cannot occur. However, hydrothermal vents are also present in shallow waters, like those surrounding Kueishantao Island, where they emerge at depths of approximately ten meters. The hot and acidic fluids released by these vents significantly alter the surrounding seawater chemistry, creating conditions that are extreme.

According to Joely Maak, “These chimneys release super-heated, highly acidic water into the overlying water columns. One might think that such an extreme location is lifeless, but it is actually vibrant with life. The vents continuously produce chemical energy in the form of reduced chemical compounds.” Dominating these ecosystems is a microorganism known as Campylobacteria. Maak describes its unique advantage derived from its use of the reductive tricarboxylic acid (rTCA) cycle. This biochemical pathway allows carbon to be converted into organic molecules and biomass with fewer energy-intensive steps compared to the more commonly known Calvin cycle. This efficiency enables Campylobacteria to thrive in extreme conditions.

Senior author Dr. Solveig Bühring of MARUM notes, “The analysis of isotope ratios has enabled us to track the carbon fixed using this ‘secret weapon’ even into the crab that lives there — a transfer that could not be detected in this way before.” This innovative tracking technique highlights the significant interactions within the ecosystem and the importance of these microorganisms in the food web.

This research contributes to the broader efforts within the current Cluster “The Ocean Floor — Earth’s Uncharted Interface,” aimed at deepening our understanding of ocean floor ecosystems amidst shifting environmental conditions and material cycles.

Source
www.sciencedaily.com