In November of 1896, two boys were bicycling on a beach in St. Augustine, Florida, and came upon a huge mass of flesh half-buried in the sand. Soon local physician DeWitt Webb was summoned to the scene. He had a team of men dig up and photograph the specimen, sending their findings to the world’s leading authorities on invertebrates. By early 1897, A.E. Verrill of Yale University had declared that the mysterious blob was a “true Octopus, of colossal size,” with tentacles over 30 meters long and suckers up to 30 centimeters in diameter. While Verrill subsequently retracted his hasty identification, other prominent naturalists continued to believe the St. Augustine “monster” was a gigantic cephalopod. The matter wasn’t settled until 1970, when a team led by Sidney Pierce analyzed the remains of the creature (which had been preserved by the Smithsonian Institution), finding them to be not a fantastic sea monster, but simply blubber from a beached sperm whale.
Hannah Waters, who works in a molecular biology lab and blogs about recent developments in all areas of biology, last week pointed out that many similar mysterious beachings have also turned out to be remains more mundane than those of a mythical Kraken. With modern DNA-sequencing tools, several attention-grabbing finds have been reclassified as whales or fish.
While fanciful tales often seem to outnumber true stories of terrifying sea monsters, there’s still plenty to fear from unfamiliar organisms. David Winters, a graduate student in evolutionary genetics, last month uncovered research on carnivorous sponges. Sponges are among our most distant relatives in the animal kingdom, lacking a nervous system, gut, and circulatory system. Most sponges are filter feeders, sweeping water through a central column with flagella and simply absorbing tiny algae and bacteria through specialized cells.
Fishers and researchers have been pulling strange sponges up from the depths for years, but it wasn’t until 1995 that a team led by Jean Vacelet finally observed carnivorous behavior in sponges. These organisms have no filter-feeding system at all, instead extending filaments covered in hooked spicules into the water, snaring passing crustaceans. They then rapidly produce new cells that entomb and absorb their prey. Last year, Vacelet worked with a new team to discover another carnivorous sponge, which appears to retain its filter-feeding apparatus. This species, Chondrocladia turbiformis, holds the vestiges of its filter above a cylindrical stalk. But instead of using the filter to eat tiny microorganisms, it inflates it like a balloon, using spicules to nab larger prey.
Unlike the hooked spicules of earlier carnivorous sponges, Chondrocladia‘s spicules are shaped more like cylinders carved with a lathe. Fossilized versions of these spicules have been found in sediments dating back 150 million years, suggesting that carnivorous sponges have been with us a very long time.
Although carnivorous sponges sound creepy, they pose little danger to humans; Chondrocladia are barely 3 cm tall. Recently, however, an organism that does present some danger has been found in the Pacific Northwest—but it’s not an animal; it’s a fungus. Jelly fungi typically grow on tree bark and can form fantastic shapes; their name comes from their resemblance to jelly fish. Some of them, like the wood-ear mushrooms often used in hot and sour soup, are even edible.
Colorado-based science writer Jennifer Frazer says this new menace, called Cryptococcus gattii, has infected 200 people and killed 24 in the last decade. How does a fungus in tree bark kill a human? It becomes a yeast. Apparently C. gattii, like many fungi, can survive both as a multicellular mushroom-like form, or as an independent singled-celled organism—a yeast. It’s the yeast form that is deadly. People breathe in the yeast cells, which can eventually lead to a dangerous lung infection. A variety of other animals, including llamas and even porpoises, have also been infected and killed by C. gattii.
A team of researchers led by Edmond Byrnes conducted a detailed analysis of the North American C. gattii outbreak and found similarities to jelly fungi from Africa, South America, and Australia. They also found that the North American populations are rapidly mutating. The research was published in PLoS Pathogens in April. While infections and death are rare among the millions of individuals that have potentially been exposed, the researchers say that the fungus warrants closer attention, in case a mutated strain ends up being more dangerous.
Frazer doesn’t see too much danger in this outbreak, pointing to much more significant killers in the form of good old-fashioned contagious diseases. But one thing is clear: You’re much more likely to get killed by unseen organisms like tiny yeast cells and tinier viruses than by mysterious “monsters” from the deep. Even when a blob from the depth turns out to be a genuine squid or octopus, it’s doubtful that it would do you any harm.
Originally published June 2, 2010