Strangely, lagoons move. Today’s surfers walk across the relics of yesterday’s drowned lakes. Barrier beaches migrated landward, emerging from the ocean just as “marine transgressions” (that’s advancing oceans, not the naughtiness of waves) slowed. Shaped in stable times, coastal lakes still don’t hang around for long. This shouldn’t surprise me – I know that, despite appearances, beaches are really rivers of sand.
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If the tides were higher, if the rivers was faster or siltier, if Australia wasn’t so seismically serene, the lagoons would fill up and dry out or be washed away, and the cormorants would have to hunt elsewhere. In fact, for all our dredging and draining, it’s happening right now. Like life itself, coastal lagoons are a transitory phenomenon, a passing pleasure.
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And then there’s the gyttja, something so very special it’s found nowhere else in Australia, and helps qualify Myall Lakes as a unique protected wetland. What is it? Well, rotting pondweed. No, I’m underselling it: it’s up to 70cm of “a highly mobile and organic mud that has a gelatinous appearance”, a “flocculent green–brown material” (Drew et al 2008), “an uncompacted, anoxic and sulphurous ‘ooze'” made from “the decomposition of charophytes, macrophytes, cyanobacteria and algae”. Strangely, not so much about the ooze in the National Parks brochures. But it’s an ooze that’s been there for, perhaps, a thousand years.