Scientists have finally uncovered the mystery behind the death of over 5 billion sea stars along the Pacific coast of North America, a crisis that has unfolded over the last decade.
These remarkable creatures, often called starfish, can have between five and twenty-four arms and come in vibrant colors like orange, purple, and green. In 2013, a strange disease began spreading from Mexico to Alaska, leading to mass die-offs. One of the hardest-hit species, the sunflower sea star, saw a staggering 90% reduction in its population during the first five years of the outbreak.
Alyssa Gehman, a marine disease ecologist from the Hakai Institute in British Columbia, describes the impact: “Healthy sea stars have puffy arms sticking straight out. The disease makes them develop lesions, and their arms eventually fall off.”
So, what caused this devastating disease? Researchers discovered it’s a type of bacteria called Vibrio pectenicida, which also affects shellfish. This conclusion comes from a recent study published in the journal Nature Ecology and Evolution. Rebecca Vega Thurber, a marine microbiologist at UC Santa Barbara, noted that this finding resolves a long-standing puzzle about this serious ocean disease.
Identifying the bacteria took years of research. Initially, scientists thought a virus was the culprit, but they later learned that the densovirus being studied was actually a harmless resident of healthy sea stars. Additionally, some previous research focused on dead sea stars that lacked the vital coelomic fluid needed for analysis.
Blake Ushijima, a microbiologist from the University of North Carolina, Wilmington, commented on the complexity of tracing environmental diseases in underwater ecosystems. He praised the research team for their insightful detective work.
Now that the cause is known, scientists have a better chance to help sea stars recover. They can test surviving populations for health, consider relocating them, or even breed them in captivity. This recovery is crucial not just for sea stars, but for the entire Pacific ecosystem. Healthy sea stars control sea urchin populations, which, if left unchecked, can devastate kelp forests—vital habitats for countless marine animals, including fish, sea otters, and seals.
Gehman calls sunflower sea stars “voracious eaters” that play a crucial role in their environment. The decline of these sea stars has allowed sea urchin populations to surge, leading to the destruction of about 95% of the kelp forests in Northern California over a decade. Kelp forests are often referred to as “the rainforests of the ocean” because they support diverse marine life.
Researchers are hopeful that understanding this disease will pave the way for the recovery of sea star populations and, in turn, the restoration of kelp forests.
This story highlights a significant challenge and opportunity in marine conservation, as experts work to protect these unique ecosystems. As we move forward, the collaboration across various fields—marine biology, microbiology, and ecology—will be vital to restoring balance in the underwater world.
Source link
Shellfish, Zoology, Mexico, Tuberculosis, Latin America, Central America, Melanie Prentice, Rebecca Vega Thurber, Science, North America, Climate and environment, Alaska, Alyssa Gehman, Climate
