Marine archaea and their functional networks in oceanic biogeochemical cycling

Abstract

Marine archaea are nowadays recognized as central elements in ocean food webs, playing key roles in global nitrogen cycling and other biogeochemical processes. Metabolic diversity enables marine archaea to exist in environments from nutrient-poor surface waters to deep-sea hydrothermal vents. Data used in this review were obtained from online databases, including Scopus, PubMed, SciFinder, ScienceDirect, Springer, and Google Scholar, with a focus on ecological functions, metabolic activities, and new biotechnological applications of marine archaea. Single-cell genomics and metagenomics have revealed new insights into marine archaeal diversity and their potential as sources of extremozymes, antimicrobial compounds, and other bioactive secondary metabolites. Such properties are promising for exploitation in biomedicine, environmental biotechnology, and industry. Cultivation, genetic manipulation, and functional characterization are now limiting commercial and research exploitation. This review summarizes the current state of knowledge on the ecological significance, metabolic diversity, and novel biotechnological potential of marine archaea, as well as their role in marine biogeochemical cycles. It provides research directions to overcome present technical limitations to utilize their full potential.