In this new post, Lu Wang, a Ph.D. student from the Institute of Botany, Chinese Academy of Sciences, China, discusses her recently published paper, “Divergent microbial phosphorous acquisition strategies between active layer and permafrost deposits on the Tibetan Plateau”. She delves into the research gap regarding phosphorus cycle in permafrost soils, highlights the challenges associated with measuring phosphorus acquisition strategies and shares her fascination for nature.
About the Research
Permafrost ecosystems cover 16% of the global land area, and their soil carbon (C) pool is approximately twice that of the atmospheric C pool. The rapid climate warming has led to widespread permafrost thaw, which could then activate microorganisms to decompose organic C stored in frozen soil. It has been estimated that permafrost thaw could release 13-16 billion tons of C each year, equivalent to about 15% of annual emissions from fossil fuels, establishing a potential positive C-climate feedback. The global change research community has vividly referred to this phenomenon as the ‘permafrost C bomb’. Due to this point, many research groups around the world, including our research group led by Prof. Yuanhe Yang, explored permafrost C cycle to understand this potential permafrost C-climate feedback and formulate the corresponding climate change policies. Up to now, previous studies mainly focused on ecosystem C dynamics upon permafrost thaw and the regulation of soil nitrogen (N) status on permafrost C dynamics. Actually, beside N availability, soil phosphorus (P) availability could also constrain the growth of both plants and microorganisms, thereby exerting crucial effects on permafrost C cycle. However, by conducting a comprehensive literature review, we were surprised to find that there was a significant research gap concerning soil P availability and its biological acquisition strategies in permafrost regions.
About the Paper
To bridge the knowledge gap mentioned above, we conducted an extensive field investigation along a 1,000 km permafrost transect on the Tibetan Plateau. Based on this large-scale sampling, we aimed to examine microbial P acquisition strategies in both the active layer (i.e., seasonally thawed surface layer) and permafrost deposits. During the stage of experimental design, the biggest challenge we met was how to quantify microbial P acquisition strategies in both the surface layer and permafrost deposits. Initially, we tried to employ 33P isotope dilution method to determine the specific rates of solubilization, mineralization and transportation. However, in our preliminary experiment, the majority of sampling sites exhibited water-extractable P concentrations (a crucial indicator for determining P transformation process) below the detection threshold even after a 20-fold concentration. Consequently, we had to discard this method for measuring actual rates. This experimental failure forced us to select another widely-used approach, shotgun metagenomics to reflect P transformation potential. By doing so, we discovered that soil microorganisms in the active layer and permafrost deposits exhibited distinct preferences for P acquisition strategies. Soil microorganisms in the active layer tended to mobilize recalcitrant P fractions into available form through solubilization and mineralization, whereas those in the permafrost deposits showed greater potential for P transportation. These findings advance our comprehension of microbial P acquisition strategies in permafrost regions, emphasizing the necessity to consider the diverse microbial P acquisition strategies across different soil layers for improving model prediction of soil biogeochemical cycle responses under climate change.
The majestic landscape on the Tibetan Plateau (credit: Lu Wang)
About the author
During my time as an undergraduate student, I had the amazing opportunity to do fieldwork, which allowed me to really connect with nature. These experiences not only fascinated me with the beauty of the natural world, but also left a lasting impression on me regarding its resilience. It was because of these reasons that I developed a strong desire to further explore the intricate relationships between organisms and their environment. Consequently, when it came time for my graduate studies, I chose to specialize in ecology and focused primarily on studying soil P cycle in permafrost ecosystems. Currently, I am fortunate enough to be a PhD student under the guidance of Prof. Yuanhe Yang at the Institute of Botany, Chinese Academy of Sciences. Moving forward, I will continue collaborating with other team members to investigate soil P dynamics, P transformation process, and explore how P interacts with other elements in permafrost regions under continuous climate change.
Like the blog post? Read the paper here.
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