Journal of Aquaculture Research & Development

Role of Marine Ammonia-Oxidizing Bacteria in Nitrogen Cycling

Xini Qui^* Department of Marine Sciences, Ocean University of China, Qingdao, China
^*Correspondence: Xini Qui, Department of Marine Sciences, Ocean University of China, Qingdao, China, Email:

Received: 24-Jul-2023, Manuscript No. JARD-23-22965; Editor assigned: 26-Jul-2023, Pre QC No. JARD-23-22965 (PQ); Reviewed: 14-Aug-2023, QC No. JARD-23-22965; Revised: 21-Aug-2023, Manuscript No. JARD-23-22965 (R); Published: 28-Aug-2023, DOI: 10.35248/2155-9546.23.14.789

Description

The world's oceans are filled with life, from the smallest microorganisms to the grandest whales. Beneath the surface of these vast bodies of water, a microscopic world of bacteria plays a pivotal role in shaping the health and balance of marine ecosystems. Among these microorganisms, marine ammonia-oxidizing bacteria hold a special place in the cycling of nitrogen, a important element for all life forms. In this article, we delve into the developing world of marine ammonia-oxidizing bacteria, their significance, and the cultivation techniques that have unlocked their secrets. Nitrogen is an essential element for life, making up a significant portion of biomolecules like proteins and DNA. In marine ecosystems, the cycling of nitrogen is a finely tuned process, critical for maintaining water quality and sustaining the diversity of marine life. Ammonia, a form of nitrogen, is produced through various biological processes, including the excretion of waste by marine organisms and the decay of organic matter. However, excessive ammonia levels can be harmful, causing toxicity to aquatic organisms. This is where Ammonia- Oxidizing Bacteria (AOB) come into play. These bacteria, which belong to the classes Beta-, Gamma-, and the recently discovered Delta- and Zeta-proteobacteria, play a central role in the nitrogen cycle by converting toxic ammonia (NH₃) into nitrite (NO_2-) and subsequently into nitrate (NO_3-), a less toxic form of nitrogen. This process, known as nitrification, not only detoxifies ammonia but also makes nitrogen available to other organisms as a nutrient source, thus promoting the overall health and productivity of marine ecosystems.

Marine AOB significantly influence nutrient cycling and nitrogen availability, which in turn affects the health and biodiversity of marine ecosystems. Knowledge of AOB can be applied to improve wastewater treatment processes by optimizing nitrification, reducing ammonia levels, and mitigating pollution in coastal areas. In aquaculture systems, controlling ammonia levels is essential for the health and growth of cultured organisms. Understanding AOB dynamics can help maintain optimal water quality in aquaculture facilities. Marine AOB have potential applications in bioremediation efforts, helping to clean up environments contaminated with ammonia and other pollutants. Culturing marine AOB in the laboratory is a challenging but rewarding endeavor. It allows researchers to study these bacteria in controlled conditions and gain insights into their physiology, genetics, and ecological roles. Researchers typically collect water or sediment samples from marine environments where AOB are known to thrive. These environments can include coastal waters, estuaries, and even deep-sea habitats. Specialized equipment is used to obtain samples without contaminating them with terrestrial AOB, which can be more easily cultured. The collected samples are inoculated into a culture medium designed to promote the growth of AOB. This medium typically contains ammonia as the sole source of nitrogen and may also include trace elements and vitamins. Oxygen levels in the culture must be carefully controlled, as AOB are aerobic bacteria that require oxygen for their metabolism. After some time, when bacterial growth is observed, researchers work to isolate and purify individual AOB strains. This is achieved through techniques such as dilution-toextinction and selective plating. The isolated strains are then maintained in pure culture to study their characteristics and behaviors. Advances in molecular biology have enabled researchers to sequence the genomes of marine AOB, providing valuable insights into their genetic makeup and metabolic pathways. Researchers conduct experiments to study the physiology of AOB, including their growth rates, tolerance to environmental conditions, and the factors that influence their nitrification activity. Understanding the ecological roles of AOB in marine ecosystems involves studying their distribution, abundance, and interactions with other microorganisms and macro organisms. The genetic diversity of marine AOB is high, and many species are yet to be identified and cultured. This diversity presents challenges in characterizing their functions and ecological roles. Marine AOB exist in complex microbial communities, and their interactions with other microorganisms can be intricate. Understanding these interactions is essential for unraveling their roles in marine ecosystems. Marine AOB are sensitive to environmental changes, making it challenging to maintain stable cultures in the laboratory.