Here鈥檚 what you鈥檒l learn when you read this story:In 2023, scientists from the Occidental College of Los Angeles collected 36 specimens of sea spider living near methane seeps along the Pacific Coast from California to Alaska. Upon examining the arachnid-like creatures, they discovered that these deep sea species form a symbiotic relationship with methylotrophic bacteria, which provide a food source in the pitch dark aphotic zone. This new study paints a more complete picture of how the deep sea helps keep methane (a potent greenhouse gas) from escaping into the atmosphere.When you live in the ocean鈥檚 aphotic zone, where absolute darkness reigns, you need some creative solutions to some pretty existential questions. Chief among them: what are you going to eat? For a variety of ocean floor-dwelling species, including mussels, worms, and sponges, that answer lies with chemosynthetic bacteria鈥攐rganisms that flourish around methane seeps where the gas escapes the Earth鈥檚 crust. A new study shows that three species of the sea spider genus Sericosura also demonstrate a similar ability, which helps explain why these spindly-legged organisms are found in such abundance near methane seeps. The results of the study were published in the journal Proceedings of the National Academy of Sciences (PNAS). Despite the name, sea spiders aren鈥檛 actually spiders (though, that鈥檒l likely be of little comfort to an arachnophobe). Although they look remarkably similar, sea spiders have a thinner cephalothorax than their eight-legged land-based lookalikes, and their legs tend to have more joints. Oh, and they also live in the deep ocean鈥攐ne of biology鈥檚 true final frontiers of scientific inquiry. This hard-to-reach ecosystem is why many aspects of their lives remain a mystery.鈥淥ur study aimed to examine the ways in which often overlooked animals might take advantage of novel energy sources, such as methane,鈥 Shana Goffredi, the senior author of the study from the Occidental College of Los Angeles, said in a press statement. 鈥淲hile the deep sea feels far away, all organisms are interconnected, and the processes in one ecosystem affect another.鈥滻n 2023, Goffredi鈥攁long with two students, including Bianca Dal B贸鈥攅mbarked on a two-week research expedition on the R/V Atlantis to study these creatures in their deep-sea habitats. With the help of a piloted submersible named Alvin, they examined and collected sea spider specimens located 1,000 meters (3,280 feet) below the ocean surface from the Del Mar and Palos Verdes seeps in California and the Sanak seep in Alaska. Of the 36 specimens recovered, three of the spiders represented entirely new species. 鈥淚 had seen animal samples in preservatives in the lab for so long, so it was beautiful to finally see them moving around in their natural habitat,鈥 Dal B贸 said in a press statement. 鈥淚t made me feel all the more connected to my project and these fascinating ecosystems.鈥漌hile performing experiments on board, Goffredi and Dal B贸 incubated the sea spiders in seawater with methanol and a heavy isotope of methane. Because this isotope is rare in nature, the researchers could track its impact on the sea spiders, including if it was ingested. They found that methylotrophic bacteria located on the sea spiders鈥 exoskeletons served as a source of a food. 鈥淓vidence from tissue isotopic analysis, microbiome sequencing, and live-animal incubations followed by 13C-methane isotope probing confirms active incorporation of methane-derived carbon into spider tissues,鈥 the authors wrote. 鈥淭his research highlights a previously unknown interaction between an animal lineage and chemically fueled microbes, introducing another symbiotic pathway for direct microbial transfer of methane carbon into animal biomass in the deep sea.鈥漈his transfer of methane carbon into animal biomass is particularly important for scientists to understand, as methane is one of the most potent greenhouse gases. Sea spiders鈥攚ith the help of other deep ocean-dwelling animals鈥攁re doing their part to keep these gases locked away in the ocean, so they don鈥檛 reach the atmosphere and exacerbate the ongoing climate crisis. 鈥淲hile the deep sea feels really far away, all organisms are interconnected,鈥 Goffredi told CNN. 鈥淓ven though they鈥檙e small, these animals have a big impact in that environment. We can鈥檛 ever hope to sustainably (use) the oceans if we don鈥檛 really understand the oceans.鈥