An effort to restore bull kelp along the Sonoma coast has received a $4.9 million boost from the federal government. Information gleaned from a test project in Drakes Bay will be used to guide the work in Sonoma, a joint effort of the Greater Farallones National Marine Sanctuary and the Greater Farallones Association, a nonprofit that supports the sanctuary. Researchers hope their work will help restore a key ecosystem, capture carbon from the atmosphere and eventually resuscitate a once-vibrant fishery that depended on bull kelp for its survival. The new funding comes from the National Oceanic and Atmospheric Administration as part of the 2021 Infrastructure Investment and Jobs Act. More than 90 percent of northern California’s bull kelp disappeared over the last decade due to warming waters caused by a marine heat wave and a disease that wiped out starfish. Kelp withers in warmer waters, and the starfish were a key predator that preyed on purple urchins, whose population surged when the starfish died off from disease. Now, purple urchins have consumed much of the kelp forests that thrived just offshore on the Sonoma, Marin and Mendocino coasts. “Kelp is an incredibly vital ecosystem along the California coast,” said Jennifer Stock, a spokeswoman for the sanctuary. Bull kelp, which grows as long as 60 feet in waters up to 100 feet deep, offers protection to threatened and endangered species like abalone and sea otters. Researchers also believe it has the potential to increase climate resiliency by capturing carbon and storing it on the sea floor  when it dies and sinks. The $4.9 million will be used to plant kelp at four locations along the Sonoma coast, where kelp forests are more accessible. But that work will be guided by an ongoing pilot project begun last year in Drakes Bay. Researchers there are testing different techniques for planting kelp, investigating four methods over the course of two years: attaching kelp spores to gravel and dropping it into the ocean, attaching spores to floating twine tethered to the ocean floor, attaching spores to clay bricks dropped on the sea floor and spreading a concentrated spore solution into the water. Before attempting to plant in Drakes Bay, the team used drones to map the area and identify locations where kelp had previously grown. They used a camera-equipped robot to plant the spores because the area was unsafe for divers. In June, the team will visit the Drakes Bay sites to determine whether the spores they planted last year have grown. The test involved using spores attached to twine tied to clay bricks that sink to the ocean floor; the twine then floats in a vertical column. “We’re hoping to transfer a lot of lessons learned from Drakes Bay to our Sonoma work,” said Rietta Hohman, the project manager. The Sonoma work will unfold over five years and will begin this summer as soon as environmental impact reviews are completed.