Unexpected coral reefs discovered in WA's turbid waters

November 22, 2023 9:07 PM

Unexpected coral reefs discovered in Western Australia's turbid waters surprise researchers. In September 2023, the turbid waters in Exmouth Gulf cleared to reveal a wonderland of undamaged black corals and healthy reefs, but marine scientists are worried the area will miss out on protection. The turbid nature of the Exmouth Gulf is affected by a mix of currents, tides and even the El Niño-Southern Oscillation which means that on an average day, the water is murky and visibility is poor. And some parts of the 2600 square kilometre water body have only gotten more turbid in the past two decades. But in September 2023, an extended window of vaunted "glass out" conditions, where the ocean is flat and reflective like a mirror, lifted the murky veil. What was revealed — in a survey by independent marine research firm Oceanwise over two weeks in September — was a diverse range of hard and soft corals including species usually found in much deeper waters like the colourful fan-like gorgonians. The researchers also discovered slow-growing black corals, so named because of the dark skeletons they leave in death.
posted by chariot pulled by cassowaries (5 comments total)

It makes sense that species adapted to deeper waters would colonize shallower, but murkier water, as they would get similar amounts of light.
posted by hypnogogue at 4:42 AM on November 23, 2023 [1 favorite]

Very cool. I was surprised that some of the shallower deep sea corals are only at 5 meters, which is very shallow.
posted by snofoam at 5:01 AM on November 23, 2023

Oh wow! I know the area around Exmouth has some close-in coral reefs. Fascinating to hear about these as well! If the Great Barrier Reef didn't exist, Exmouth would be world-famous instead of Australia's best-kept secret.
posted by rednikki at 5:50 AM on November 23, 2023

Strange to me that they're surprised. We have incredible reef-like biodiversity in the Salish Sea in very "murky" waters (cold, dark, and green). The murk here is full of nutrients, and turbidity and currents lead to incredible diversity of filter feeders and other life on rock walls and other structure -- anemones, cloud sponges, soft corals, tubeworms, other sponges... if it was easier to link a picture on Metafilter I'd post one from Deception Pass for you to goggle at!
posted by cnidaria at 9:25 AM on November 24, 2023

Can they survive at these depths without the turbidity?
posted by inexorably_forward at 6:12 PM on November 24, 2023