A guide for closed circular aquaculture systems farming North Sea biota: An overview on the key biogeochemical cycles and the role of the North Sea benthic microbial communities in the nitrogen cycle.

Abstract

The oceans are dominated by microbial communities which play a central role in the biogeochemical cycling of elements on Earth. In order to create natural, circular, animal-friendly, and resilient aquaculture systems, aquaculturists must strive to understand these complex biogeochemical processes to replicate natural conditions and maintain resilience to disequilibrium. The aim of this review is to provide a comprehensive understanding of the biogeochemical cycles of carbon, nitrogen, phosphorus, and sulfur and the role of these elements in living organisms, whilst going into detail on the role of the North Sea seafloor microorganisms on the nitrogen cycle to improve their understanding and management in closed circular aquaculture systems farming North Sea biota. The paper also reviews the physical and ecological characteristics of the North Sea seafloor sediments, which consist of permeable sands, also referred to as ´biocatalytic filters` due to their ability to stimulate microbial activity by trapping dissolved and particulate organic matter from the water column. We subsequently highlight the reasons for the ecological importance of maintaining the biogeochemical cycles, especially the N cycle, in a healthy balance, and present the key concepts aquaculturists farming North Sea biota must take into account to maintain this balance. We conclude the review with a summary of the critical knowledge gaps which must be considered in future research on this topic to aid in the management and creation of more sustainable and self-supporting closed circular aquaculture systems.