A vital aspect of Rebma's environment, known and instinctively utilized by all the Sea's natural denizens, is the movement of currents: Cohesive streams of water within the larger body. While many are randomly generated and relatively short-lived, as by the passage of ships, storms, or anything of mass or force which displaces water in certain directions, there are those currents which run a dedicated circuit directed by the geological constants of terrain, temperature, water densities, and regular weather patterns, as well as some element of mysterious force in place which makes currents extra fantastic. Two distinct systems exist in Rebma, the upper level of currents directed by wind circulation and nearby landforms, and the deep level currents influenced by the surface movements as well as a variety of conditions present over the vastness of the seafloor.
Occurring between about 1300ft (400m) depth and sea level, these wind-directed movements determine which way a drifting object drifts, and affect how quickly sailing ships reach their destinations even at full sails. Having a full working knowledge of their circuitous behaviors give sea captains an advantage over competitors in matters of commerce and war. The presence of the Rebman Triangle over an area of water through which currents draw ships more rapidly towards Amber than the usual channel demonstrates nicely the value of a passage treaty with the Rebman Crown Authority. Of the two systems, surface currents are considered safer for travel, easier to pull oneself out with a timely dive, should there be trouble brewing ahead.
Below 1300ft (400m) depth and typically encountered closer to the sea floor, there are masses of moving water varying in size and speed, fed by the upper level currents and sweeping up every drifting thing in their path. As the surface currents are akin to the winds of the undersea realm, these are much the equivalent of rivers, albeit more complex in scope. The most well-known is the East Rebman Current (ERC) which begins north of the capital and swoops southeast around the undersea mountain, barely brushing through the breathable limits as it rushes southward into the wide open territory. According to adventurous types such as Selkies, by hopping from current to current at the right points, a person could ride to the farthest reaches within a day or so, with many wondrous sights and perils along the way. To date, no one who has attempted to verify these claims has returned, for many currents are difficult to escape once caught, and the ways are truly dangerous. The rare survivor who bailed out early and returned with the help of military recon specialists might speak of yawning dark chasms and disturbing sound anomalies, too disoriented to pinpoint their location at any given time.
The currents contribute to keeping much of the realm a mystery even to denizens, although those races with tribal territory and Rebmans who live on the noble holdings have staked out tried and true safe routes to and from the capital which make careful use of some currents to help speed the journey.
The Shadow boundaries of Rebma undersea territory are marked by current turbulence and a large variety of changing characteristics which make travel beyond hazardous and uncertain. They coincide with the Shadow boundaries of Amber surface waters, where the entrances to Shadowpaths can be accessed at certain coordinates. The shadow seas cannot be effectively traveled by the swimming denizens unless they have gained the secret wisdom of the Single Sea, an esoteric philosophy that joins all large bodies of water across Shadow. Most settlements and holdings are far enough away from Wild Waters to not be unduly affected, with the notable exception of the March of House Bauquemare, which sits the rocky edge.