Probiotics: fishing in the ocean

Probiotics are live, non-pathogenic microorganisms that confer health benefits by modulating the gut microbiota. The human gastrointestinal tract harbors a complex microbial ecosystem, and the balance of this microbiota is crucial for digestive and systemic health. Among the most extensively studied and utilized probiotics are species formerly classified within the genera Lactobacillus and Bifidobacterium. These organisms not only naturally colonize the human gut but are also consumed through...

The deep ocean and its underlying sediments represent vast, largely unexplored microbial habitats that extend far beyond the sunlit photic zone. The photic (euphotic) zone typically spans the upper ~100–200 meters of pelagic waters in the open ocean, but its depth varies geographically and seasonally, where sufficient light supports photosynthetic life. Below this lies the deep sea, spanning roughly 1000–6000 meters (bathypelagic to abyssal zones), with deeper hadal trenches extending beyond...

Marine microbial ecosystems are shaped by distinct physicochemical limits, including high salinity, low nutrient availability, and fluctuating oxygen levels. These conditions favor smaller microbial cell sizes, which maximize their surface-to-volume ratio for efficient nutrient uptake.Microbial activity and community composition are closely linked to biogeochemical cycles, particularly in dynamic environments like estuaries, where halotolerant microbes thrive in response to variable salinity...