One Maine-based startup, Running Tide Technologies, is experimenting with farming kelp, a type of seaweed, in an effort to pull carbon from the air and store it deep beneath the ocean floor, potentially giving the world another nature-based tool to curb climate change.Running Tide Founder Marty Odlin, a Dartmouth graduate and engineer whose family includes generations of fishermen, is working with a team of engineers, software developers, oceanographers, maritime professionals, data scientists and hatchery technicians to bury massive amounts of kelp