Microbial Nitrogen Cycling in Estuarine and Coastal Ecosystems

Dear Colleagues,

Over the past five decades, human activities have doubled the nitrogen (N) loading on the Earth’s system. The marine N cycle is driven by various biogeochemical transformations mediated by microorganisms. These processes include contributions to the marine fixed N pool (such as N₂ fixation) and the retained N pool (including nitrification, assimilation and dissimilatory nitrate reduction to ammonia). Additionally, there are processes that contribute to fixed nitrogen loss (such as denitrification, anaerobic ammonium oxidation and nitrite-dependent anaerobic methane oxidation). The N cycle is essential for the functioning of marine ecosystems and will play a crucial role in how the ocean responds to global environmental change. With rapid economic development and extensive human activities, significant amounts of pollutants and reactive nitrogen have been transported by upstream rivers into estuarine and coastal areas in recent decades. This influx has led to a considerable degradation of water quality. Estuarine and coastal ecosystems are vital components of the nitrogen cycle and can also act as potential sources of nitrous oxide (N₂O). Microorganisms are the key drivers of nitrogen biogeochemical cycles. Most pollutants can impact microbial growth, metabolism, activity, diversity and function. Microbial networks involved in nitrogen transformation can both mitigate and exacerbate human-induced global change. They play a role in the production and consumption of the potent greenhouse gas N₂O, contribute to the eutrophication of aquatic systems and simultaneously aid in nitrogen removal from wastewater. Given the intimate relationship between microorganisms and nitrogen cycles, further exploration of their coupling mechanisms and ecological and environmental impacts in estuarine and coastal areas is necessary.

This Special Issue aims to investigate nitrogen cycling processes in estuarine and coastal ecosystems, as well as microbial-mediated nitrogen biogeochemical processes and their coupling mechanisms. Furthermore, we also focus on the impacts of key pollutants on the nitrogen cycling process and its associated microorganisms.

This Special Issue calls for original and novel manuscripts related to nitrogen elements in estuarine and coastal areas with any of the following sub-topics:

• Research on nitrogen pollution in estuarine and coastal ecosystems: sources, transformation, fluxes and effects;
• Nitrogen transformations in estuarine and coastal ecosystems, including spatiotemporal variations, release of greenhouse gases (N₂O), controlling factors and environmental implications;
• Key processes and coupling mechanisms of nitrogen cycling driven by microorganisms;
• The utilization of novel techniques in identifying microorganisms and their involvement in carbon and nitrogen cycling processes;
• Impact and mechanism of key pollutants on sedimentary microbial communities and nitrogen cycling.

We are looking forward to receiving your contributions.

Dr. Pengfei Sun
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Microorganisms is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2700 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

• nitrogen cycling
• processes
• nitrous oxide
• pollutions
• functional genes
• microbial ecology
• estuarine and coastal ecosystems
• greenhouse effect
• eutrophication