Isabella Miller A person walking the beach in Maui in late October 2023 spotted something so unusual they stopped and called the refuge manager before taking another step. The pond at the Kealia Pond National Wildlife Refuge had turned completely pink. Not slightly off colour but a full bright bubblegum shade sitting there in broad daylight with no explanation attached to it. Nobody at the refuge including volunteers who had monitored the site for seventy years had ever seen the water do anything like this before.
Nobody Had Seen This Before
Seventy years of monitoring and not one person could recall the water ever changing colour this dramatically. Even during previous droughts the pond had stayed the colour water is supposed to be.
Toxic Algae Got Ruled Out
The refuge manager suspected an algae bloom first because that was the most logical explanation available. Lab tests came back negative and the search for an actual answer had to start again from scratch.
Halobacteria Pointed the Way
Water samples sent to the University of Hawaii came back pointing toward halobacteria. These single celled organisms live in extremely salty water and naturally produce a pink pigment as part of their basic biology.
Salt Levels Were Extreme
Salinity inside the pond outlet measured greater than 70 parts per thousand which is more than twice the salinity of normal seawater. That level gave halobacteria exactly the conditions they need to multiply fast and colour everything around them.
Drought Set Everything in Motion
Waikapu Stream normally feeds freshwater into Kealia Pond regularly. The ongoing drought had stopped that flow and without the freshwater input the salinity kept climbing until conditions reached a point the refuge had apparently never hit in its recorded history.
Rain Should Bring It Back to Normal
Freshwater from the stream returning after rainfall should dilute the pond enough to pull salinity down and gradually shift the colour back. The bacteria thrive precisely because the conditions currently favour them and changing those conditions is what eventually stops them.
People Came Just to See It
Photos spread quickly online and visitors started arriving specifically to look at the pink water. The refuge manager said that if a bubblegum coloured pond was what brought people through the gates then that worked for him.
Nobody Should Go in the Water
Scientists warned against entering or drinking from the pond while the situation continued. The extreme salinity and bacterial concentration make it genuinely unsuitable for contact regardless of how striking the colour looks from the shore.
This Has Happened Elsewhere Before
Halobacteria are responsible for pink colouring seen in salt lakes across Australia, parts of Europe and the Dead Sea region. What made Kealia unusual was the speed of the transformation and the fact that a wildlife refuge pond in Maui had apparently never before reached the conditions needed to produce it.
