Océane Attlan, PhD candidate at the University of Western Australia Oceans Institute

5 30 am: “dring dring” – Alarm ringing

It is time to get up, put on my wet swimsuit from the previous day, grab a quick breakfast and prepare our scientific gear. Camera batteries are fully charged, and I ensure I have all the essentials: transects, measuring tapes, waterproof notepads, and an ample supply of pencils. Pencils, they are our lifeline as marine ecologists – rule number one: always have plenty of pencils. Underwater, losing your only pencil means there is no chance to record data, a luxury that land ecologists don’t have to worry about. Pencils. Everyone is ready? Dive tanks are loaded onto the boat and secured. Our dive equipment is set up, making sure there are no leaks or ominous “pschit” sounds coming from our dive regulators.

6 30 am: “Clear!”

It is time to drive the boat down to the Port Gregory beach. Locals are here for an early morning support. Tyre pressure is lowered, readying ourselves to drive onto the sandy shore. The driver backs the trailer into the ocean, knee-deep. The skipper is ready to manoeuvre the boat, boat is free, free to go! The car is left behind on the beach while us scientists, we embark on our adventure into the wild and remote ocean of Western Australia.

8 00 am: “10m, 5m, 1m DROP!”

Here is our dive site. It is time to slip into my wet wetsuit, nice and cosy. Mask and fins on, my dive tank is opened, filled with 250 bars of air, enough to last an hour underwater. I am ready to roll. Immersion underwater.

First sight: this should be a kelp forest, there should be kelp everywhere, swaying to the rhythm of wave motion. This seascape is still – there are no kelps to be seen. Only bare rocks covered with filamentous seaweeds. And corals! Coral colonies, here, more than 500km south of Ningaloo Reef, the tropics.

We need to unravel the mechanisms behind this ecosystem shift and understand the ecological processes associated with this newfound community. After the 2011 marine heat wave, our golden kelp has retreated from warm waters, leaving space for corals to establish themselves, even this far south of Ningaloo Reef. This leave us with numerous questions: How fast do these corals grow? How much calcium carbonate do they produce? Do they exhibit similar ecological traits to their tropical counterparts? What are the consequences of this shift for habitat provision? And sediment generation?

With the help of a dive buddy, we collect the most abundant ones, some plating and branching Acropora spp., along with other species with massive or tabulated shapes. These samples are secured in an esky for our journey back – it is time to measure them.

5 00pm: “Please, do not get bogged.”

It is time to retrieve the boat. We cautiously reverse into the water, ready to deploy recovery gear in case of bogging. Our supportive Port Gregory locals stand by, ready to lend a hand if our wheels start spinning and not moving forward. Today, we are lucky, the boat is back onto the trailer without any issues. We head back to the Port Gregory campground, where a long night of work awaits us. Like skilled surgeons, we glue our specimen onto tiles, we measure and photograph them. They will spend the night with us at the accommodation before returning to their natural habitat, slowly accumulating calcium carbonate. In three months, I will return to assess their growth and compare my findings with previous studies. I am looking forward to seeing them again and studying how they slowly but surely modify ecological processes of kelp forests.

Until next time, happy calcification!

Océane Attlan is a recipient of a 2023 Holsworth Wildlife Endowment Grant.