Last Updated on June 23, 2024 by Steve Weinman
Hawaiian high-school student Maddux Springer was diving in Kaneohe Bay, Oahu during the Covid-19 pandemic when he started noticing the number of green turtles displaying large tumours all over their bodies.
The problem, it turned out, was not new – but its disturbing root cause had never been pinpointed.
His observations led Maddux to spend the next two years researching the issue. Now 18, just graduated from Iolani School in Honolulu and preparing to study marine biology at the University of Oregon this autumn, he is also set to meet Hawaii’s governor to discuss ways of tackling the problem – which, it seems, has flagged up a much bigger one.
This summer he is continuing his green turtle studies through a National Oceanic & Atmospheric Administration (NOAA) internship, and his initiative on the turtles’ behalf is already bringing rewards.
It has just won him the Society of Science’s Peggy Scripps Award for Science Communication and a prize of US $10,000 at the 2024 Regeneron International Science & Engineering Fair, said to be the world’s biggest pre-college science & technology competition.
The research
“I would both freedive and scuba dive in Kaneohe Bay, but for this research I mainly freedived because of the nature of photographing and examining the green sea turtles as efficiently as possible,” Maddux told Divernet. “I also had to use a kayak to access the study-sites, making it difficult to get all my dive-gear out.
“It felt as though every other turtle had a tumour, so I set out to try to figure out what they were.” After online and archival research had failed to turn up a cause for the disease, which Maddux believed to be fibropapillomatosis (FP), he contacted professors at the University of Hawaii for guidance.
FP causes cauliflower-like tumours to form on a turtle’s skin, including the eyes, mouth and internal organs. Agreeing that the disease remains insufficiently understood, researcher Dr Celia Smith helped him with an intensive literature review.
This led the student to the hypothesis that it was the algae on which the turtles grazed (Gracilaria salicornia and Codium edule), rich in the amino acid arginine as a result of nitrogen in wastewater pumped into the bay, that could be promoting the latent herpesvirus that causes FP.
To prove this, Maddux embarked on a three-part programme, assisted by two research advisors at his school and fellow-students. The sizeable task was to test the nitrogen and arginine content in the algae and carry out censuses both of native versus invasive algae, and of the incidence of FP in the green turtles.
He took 60 tissue samples from algae in three study locations in Kaneohe Bay, and submitted this for mass spectrum analysis. This provided its nitrogen delta 15 content, an indicator of the presence of human wastewater, from which Maddux was able to calculate the arginine tissue content.
“I then took 20 photographs along two 70m transect lines placed 10m apart every 200m throughout each study location to determine the species of algae and the native versus invasive algae rate,” he explains.
Finding a solution
That was just the start of the diving challenge. Maddux then had to dive for around 400 hours, photographing green turtles in each location using underwater cameras backed up by drone shots to determine the rate of FP among them.
“I determined whether a turtle was FP-positive based on the prevalence of tumours on their skin, distinguishing the individual turtles via their shell patterns,” he says.
He concluded that wastewater levels, arginine values, invasive algae rates and FP rates were all significantly correlated – meaning that wastewater was the likely cause of the disease contracted by the turtles as they consumed the nitrogen- and arginin-loaded algae.
The tumours were not all external, it turned out – they were inside the turtles’ bodies too, and had become their primary cause of death, before which they disabled them by inhibiting their foraging, mobility and organ functions.
“There is currently nothing being done about this issue, despite the mounting evidence,” says Maddux. “The wastewater that the algae uptakes comes from cesspools, and there are around 11,000 cesspools in Oahu. These release about 51 million gallons [more than 230 million litres] of raw sewage into our nearshore environments every day.”
Current legislation in Hawaii dictates that cesspools do not have to be diverted to wastewater treatment facilities until 2050, which Maddux Springer reckons is unacceptable.
“Once I get my research published, I’m going to try to petition the state to make this date far closer to the present. If this date stands, it will not only decimate turtle populations but also the coral populations, because turtles are a keystone species that eat the algae that smothers corals.
“Without the turtles, the corals will also face grave threats.”
(Photography by Maddux Springer)
Also on Divernet: GREEN TURTLE SEX-BIAS: NEW CAUSE FOR CONCERN, THE TURTLE THAT HOLDS UP THE WORLD, SEA TURTLES ON THE BRINK, HOW FAKE EGGS COULD BOOST TURTLE SURVIVAL
