Xibin Sun: Divergent responses of symbiotic and asymbiotic N2 fixation to seawater additions

In this post Xibin Sun, phd candidate at Sun Yat-sen University, shares the insights of his paper ‘Divergent responses of symbiotic and asymbiotic N2 fixation to seawater additions’, presents his future research plans and shows his love for their study site landscapes.   

What’s your paper about?

Author Xibin Sun, PhD Candidate, Sun Yat-sen University
Author Xibin Sun, PhD Candidate, Sun Yat-sen University

This paper reports responses of symbiotic N2 fixation (SNF) and asymbiotic N2 fixation (ANF) to seawater additions. We selected two N2-fixing species and ten non-N2-fixing species that are typical in tropical/subtropical coastal regions, and conducted a seawater addition experiment for 1.5 years. The SNF rates of two N2-fixing species and the ANF rates of all studied species were measured in situ. The results shown in this paper improve our understanding of N dynamics in coastal ecosystems in the context of sea level rise.

What are the key messages of your article?

This study, for the first time, used a seawater addition experiment to investigate effects of seawater intrusion on N2-fixing rates of ecosystems. We found that seawater additions increased SNF rates, but the responses of the two N2-fixing plant species exhibited different patterns: Casuarina equisetifolia (an actinorhizal plant) showed more tolerance than Acacia auriculiformis (a leguminous plant) under the high seawater addition. By contrast, seawater additions decreased ANF rates in rhizosphere soils across all the plant species.

What would you like to do next?

Next, we will focus on the effects of N2-fixing plants on neighboring non-N2-fixing plants. According to previous studies, N2-fixing plants may promote, inhibit, or have no effect on the growth of neighboring non-N2-fixing plants. This is inconsistent with our previous perception that N2-fixing plants provide N to surrounding non-N2-fixing plants and facilitate the growth of non- N2-fixing plants. Therefore, we want to design experiments to explain this phenomenon and to clarify what factors drive these divergent effects.

Corresponding author: Dr. Hao Chen, Associate professor, School of Ecology, Sun Yat-sen University
Corresponding author: Dr. Hao Chen, Associate professor, School of Ecology, Sun Yat-sen University

What’s your current position?

This paper is part of my research work during my master’s degree at the Institute of Subtropical Agriculture, Chinese Academy of Sciences. Now, I am a PhD candidate at Sun Yat-sen University. I will continue my previous research area on biological N2 fixation, but I am also interested in a new research area, namely leaf nutrient resorption.

What do you do in your spare time?

In my spare time I enjoy photography, which makes me get closer to nature and discover its beauty. Although the fullness of my research work makes me seldom reach for distant landscapes, the scenery around me is also excellent.

Read the research behind the story here

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