sydney reef
G Crouch

Until a few decades ago, reefs near Sydney, Australia were covered in brown, sinuous macro-algae called Phyllospora comosa, or crayweed. Then Sydney dumped a bunch of sewage in the ocean in the 1970s and 1980s and killed most of it off. Reefs were barren at worst; at best, they were covered in simpler algae. But a group of scientists just tried transplanting a new crop of crayweed onto the reefs, like giving them hairplugs. And it worked.

Live Science reports:

The transplanted crayweed not only survived similarly to those in natural populations, but they also successfully reproduced,” Alexandra Campbell, from the University of New South Wales (UNSW), said in a statement. “This creates the potential for a self-sustaining population at a place where this species has been missing for decades.”

The transfer wasn’t fail-proof — the algae did better in some places than others. But the fact that it’s even possible to grow crayweed in these places again is a good sign.