Two of the main drivers speciation among aquatic vertebrates are physical isolation (e.g., lakes and streams) micro-niche availability tropical reefs). In both regards, mesopelagic domain open ocean, Earth’s second largest cumulative ecosystem (behind only bathypelagic domain), would seem retardant. Ocean circulation makes rare on contemporary geological time/space scales, lack substrate preclu...

Yearling common barbel (Barbus barbus L.) were fed four purified casein-based diets for 6 weeks in outdoor cages. Besides control diet, these were supplemented with 0.3 mg kg(-1) dw selenium (Se) from sodium selenite, or 0.3 and 1.0 mg kg(-1) from Se-enriched microalgae biomass (Chlorella), a previously untested Se source for fish. Fish mortality, growth, Se accumulation in muscle and liver, an...