The Amazon meets a black water tributary. 
Carlo Ferroni’s Macroday is up and running with its first Sunday photo challenge: Fluid
Fluid:
adj 1: subject to change; variable; “a fluid situation fraught with uncertainty”; “everything was unstable following the coup” [syn: unstable] 2: characteristic of a fluid; capable of flowing and easily changing shape [syn: runny] 3: smooth and unconstrained in movement; “a long, smooth stride”; “the fluid motion of a cat”; “the liquid grace of a ballerina”; “liquid prose” [syn: flowing, fluent, liquid, smooth] 4: in cash or easily convertible to cash; “liquid (or fluid) assets” [syn: liquid] 5: affording change (especially in social status); “Britain is not a truly fluid society”; “upwardly mobile” [syn: mobile] n 1: a substance that is fluid at room temperature and pressure 2: a continuous amorphous substance that tends to flow and to conform to the outline of its container: a liquid or a gas
This photo is not a macro (obviously) so it won’t be headed off to competition, but I liked Carlo’s effort and am herewith making a plug for his site to the photographers out there who might’ve been hankering for a place that catered to macrophotography.