Photographer Kent Smith snapped this photo of glacial waters from Alaska rivers merging with the darker blue waters of the Gulf of Alaska while on a cruise on July 10, 2010.
A picture from the Gulf of Alaska that has been making the rounds on the Internet for the last few years — though particularly in recent weeks — shows a strange natural phenomenon that occurs when heavy, sediment-laden water from glacial valleys and rivers pours into the open ocean. There in the gulf, the two types of water run into each other, a light, almost electric blue merging with a darker slate-blue.
Informally dubbed “the place where two oceans meet,” the explanation for the photo is a simple one, though there are many misconceptions about it, including that catchy title. In particular on popular link-sharing website Reddit, where users have on multiple occasions erroneously attributed the photo’s location as “Where the Baltic and North Sea meet” and the two types of water as being completely incapable of ever mixing, instead perpetually butting against each other like a boundary on a map.
Once these glacial rivers pour out into the larger body of water, they’re picked up by ocean currents, moving east to west, and begin to circulate there. This is one of the primary methods that iron — found in the clay and sediment of the glacial runoff — is transported to iron-deprived regions in the middle of the Gulf of Alaska.
As for that specific photo, Bruland said that it shows the plume of water pouring out from one of these sediment-rich rivers and meeting with the general ocean water. It’s also a falsehood that these two types of water don’t mix at all, he said.
“They do eventually mix, but you do come across these really strong gradients at these specific moments in time,” he said. Such borders are never static, he added, as they move around and disappear altogether, depending on the level of sediment and the whims of the water.
There is much study being conducted on how this iron influences marine productivity, in particular its effects on the growth of plankton, which Bruland referred to as “the base of the food chain.”
But rivers aren’t the only way that glacier sediment finds its way into the Gulf of Alaska — occasionally strong winds can whip up enough silt to create a cloud of dust that’s visible even from space as its being carried out to sea.
So next time somebody shares a “really cool photo” of “the place where two oceans meet,” feel free to let them know the science behind the phenomenon. After all, in this Internet age, nothing spreads faster than misinformation.