Long Ones, Short Ones, Itsy, Bitsy Polychaete Worms
The incredible diversity of marine worm species around Calvert Island.
Worms often elicit disgust—the wriggling, the writhing. But the worms in the vials and dishes stacked on Leslie Harris’s desk—not to mention her infectious enthusiasm for the creatures—could make anyone a wormophile. There’s a brilliant snow-white scale worm the size of a grain of rice; a thread-like, lime green wriggler edged with tiny legs that undulate like waves; and a worm with a tangle of filamentous vibrant red gills—its respiratory system, flush with blood. Harris is clearly a fan of this latter specimen. It’s a spaghetti worm, she explains, named after the mass of tentacles that resemble a dumped pot of spaghetti on the seafloor. But she’s not one to pick favorites. “All worms are wonderful,” she says, “And if it’s not a polychaete, it’s just a wannabe.”
Although many animals are referred to as worms—ribbon worms, peanut worms, and flatworms, for instance—the worms she loves are segmented. They’re comprised of a series of identical segments, with a distinctive head and tail region. These marine worms are called polychaetes, characterized by their segmentation and bristly appendages (their name means many bristles). This class of worms doesn’t need wannabes to bump up their species count. The diversity is already dizzying.
Harris, from the Natural History Museum of Los Angeles County, is a taxonomist who specializes in polychaetes. She’s sharing her expertise with the Smithsonian MarineGEO bioblitz currently underway at the Hakai Institute’s Calvert Ecological Observatory. And it’s a good thing she’s here because in the early days of the three-week project to collect and catalog the marine invertebrates of the region, it’s clear that polychaetes rule.
At the end of the third day of sampling, Harris had already collected about 60 species and estimates that at least 10 of them are new to science. “I have another 20 more [polychaetes] on my desk that I’d like to finish up tonight,” she says. Nearing the end of the bioblitz, that number has ballooned to more than 220 species.
Polychaetes make their homes in almost every ocean habitat—from polluted mud to coral reefs, from the Antarctic to deep-sea hydrothermal vents. “You’ve ones that swallow mud and digest the organics, there are carnivores and parasites, herbivores, and filter feeders.” And there are even those that Harris calls “switch hitters”—if the current is flowing they’ll wave their appendages in the water to capture food; when there’s no current, they’ll spread the appendages across the seafloor to capture detritus.
With such a huge diversity, it’s no wonder that they play a significant role in marine ecosystems, including in the northeastern Pacific, where many species rely on invertebrates as a food source. “Here in the temperate zone, a lot of that [invertebrate] biomass is made of amphipods [a shrimp-like crustacean] and polychaetes,” says Gustav Paulay, of the Florida Museum of Natural History who leads the team of taxonomists at the Calvert Island bioblitz. “The system here is very driven by those invertebrates.”
Since the bioblitz began, Harris has been spending long days in the lab, starting about 8 a.m. and often going past midnight. It’s particularly exciting to have access to live specimens since Harris can view the polychaetes when they are still squirming.
“Most identification is done with preserved material, but it’s a lot easier [to identify] live animals,” she says. Color patterns, or distinctive behavior such as whether a worm swims like a snake or in a whirling corkscrew motion, for instance, adds behavioral detail to the description and is so much more interesting.
Harris has yet to be out in the field to collect specimens and the new rain gear she purchased before coming is still unused. But she’s content. “Some people see me as a lab slave and that I have this invisible chain and manacle tying me to the microscope,” she says, “but I prefer to think of myself as the Lab Queen with my minions bringing me samples.”
The hierarchy is in jest, of course, and Harris is genuinely thrilled when new samples arrive at her makeshift lab space. As biologists head out into the field in the morning—to the rocky intertidal, or mudflats, or seagrass meadows—she cheerily sends them off with, “Bring me worms!” And they do. Lots.
Just how many they’ll bring will be answered at the end of the bioblitz on August 11, or, more specifically, when all of the DNA analysis is complete. Given their diversity and tenacity, and the fact that polychaete taxonomists are nowhere near as abundant as the worms, the absolute number of polychaetes in this region of the Pacific will likely never be answered. But Harris is certainly giving it her best shot.