During the American Civil War, Confederate Navy officer Raphael Semmes spent years at the helm of the cruiser CSS Alabama, a ship recognized today as the most successful commerce raider in maritime history. During her time in service, Alabama would claim a total of 65 prizes, boasting a record that remains unsurpassed in its performance on many counts.
No doubt due in part to this success, Captain Semmes was promoted to the rank of rear admiral, and even served a stint for a period as brigadier general in the Confederate States Army, although the temporary position was never confirmed by the Confederate Senate. However, a less well-known historical detail about Semmes and his period in service during the War Between the States involves his encounter with an unusual phenomenon while at sea, which the captain recounted in his 1887 memoir Service Afloat, or the remarkable career of the Confederate cruisers Sumter and Alabama, during the war between the states.
The incident in question occurred on the evening of the 29th of January, 1864. As Semmes and his crew sailed along near latitude 2° 43’ north and longitude 51° east, they found themselves sailing through “a remarkable patch of the sea.” Remarkable indeed, for rather than the usual blue tint of ocean water, the sea suddenly appeared to have taken on a milky white appearance.
As Semmes wrote of the incident, “At about eight P. M., there being no moon, but the sky being clear, and the stars shining brightly, we suddenly passed from the deep blue water in which we had been sailing, into a patch of water so white that it startled me; so much did it appear like a shoal. To look over the ship’s side, one would have sworn that she was in no more than five or six fathoms of water. The officer of the deck became evidently alarmed, and reported the fact to me, though I myself had observed it.”
Semmes and his crew were alarmed by the sea’s appearance. Had they sailed off course? Could they have inadvertently sailed into a shallow shoal, which might place them at risk of becoming stranded? Semmes and his crew dropped a line to take depth measurements but were unable to locate the sea floor and, with some of their concerns now removed, turned their attention back to the unusual, ghostly glow that was being produced from within the surrounding sea.
“My fears thus quieted, I observed the phenomenon more at leisure,” Semmes wrote. “The patch was extensive. We were several hours in running through it. Around the horizon there was a subdued glare, or flush, as though there were a distant illumination going on, whilst overhead there was a lurid, dark sky, in which the stars paled.”
Semmes imagined that any other sailors adrift in the nearby sea might have mistaken his ship in this subtle glow for being a phantom ship, “lighted up by the sickly and unearthly glare of a phantom sea.” However, rather than actually concluding that there had been some unnatural phenomenon at work, upon sailing for some time through the eerie pale glow Semmes and his crew decided to take a closer look at what might have produced it.
“Upon drawing a bucket of this water,” Semmes tells us, “it appeared to be full of minute luminous particles; the particles being instinct with life, and darting, and playing about in every direction.” Semmes and his crew could tell that the light was a product of tiny bioluminescent organisms congregating near the ocean surface. Semmes added that “upon a deck-lantern being brought, and held over the bucket, the little animals would all disappear, and nothing but a bucket full of grayish water would be left.”
The peculiar phenomenon Semmes described may represent one of the earliest written accounts detailing strange appearances of “milky” patches of ocean, a phenomenon which has been documented by sailors over the years on a number of occasions, some of whom even detected the curious manifestations on radar. While even early accounts like those of Semmes associate the appearances of milky seas with bioluminescent organisms, some aspects of the phenomenon remain a mystery.
We haven’t solved the mystery of the milky seas,” according to Steven Miller, a senior research scientist at Colorado State University who was interviewed by the BBC about the phenomenon. “We have been able to detect them but there is not concrete evidence of how they form, why they form… we just need to find out a lot more about it,” Miller said.
Thus, the strange discoloration of ocean water filled with bioluminescent bacteria, while long recognized by sailors at sea, remains somewhat elusive to scientists who attempt in modern times to understand its underlying causes.