CNN’s Wonder Theory science newsletter invites you to explore the latest discoveries on fascinating creatures and scientific advancements. Recent research suggests that three previously unknown sea spider species have formed a unique symbiotic relationship with bacteria in deep-sea habitats known as methane seeps.
The bacteria convert carbon-rich methane and oxygen into sugars and fats, which are then consumed by the sea spiders. This unusual nutrition strategy has never been observed in sea spiders before. According to Shana Goffredi, principal investigator of the study, “Just like you would eat eggs for breakfast, the sea spider grazes the surface of its body, and it munches all those bacteria for nutrition.”
The newly discovered Sericosura species lack the necessary appendages to capture prey, making them more akin to farmers harvesting methane-fueled bacteria from their own bodies. Goffredi believes that the spiders and their microbes may play a crucial role in preventing methane from reaching Earth’s atmosphere.
Studies have shown that microbes use chemicals for energy instead of sunlight in the deep-sea ecosystem. When marine life dies, it sinks to the seafloor and becomes buried, releasing methane gas. The microbes attach themselves to sea animals to remain among the bubbles, where they can feed on the methane.
The discovery of these rare sea spiders highlights the importance of understanding the oceans’ ecosystems. As Goffredi said, “While the deep sea feels really far away, all organisms are interconnected. Even though they’re small, these animals have a big impact in that environment.” Further exploration of the seafloor could uncover additional similar species and provide insights into how humans’ gut bacteria is passed between mothers and newborn children.
The study’s findings also emphasize the need for caution when using the seafloor for mining or other activities. As Goffredi noted, “People tend to think of the deep sea as a kind of homogeneous ecosystem, but that’s actually untrue. There’s a lot of biodiversity by region and animals are very localized to specific habitats on the seafloor.”
Source: https://edition.cnn.com/2025/06/17/science/spiders-deep-sea-methane-new-species