One of the delights of childhood for those lucky enough to live near the coast is peering into rock pools.
I think it has something to do with a rock pool being child-sized, where a youngster can see a whole living world in a small space. I remember the fascination of watching tiny fish dart among the seaweed, and the thrill of touching a finger tip to a sea anemone and watching it whip away its coloured tentacles, and then slowly unfold them again once the “danger” had passed.
Rock pools are wonderful outdoor classrooms too. But what if your childhood coastal experience was not of beaches and rock pools, but concrete seawalls? What would you see of marine life? Well, not much, as a concrete wall is not an attractive place for marine life. Now some clever people are working to change that. It is called eco-engineering, and although by no means a cure, it goes some way to putting back some of what has been destroyed. I heard Dr Louise Firth from Plymouth University speak about eco-engineering last week, of how coasts around the world had been radically altered by humans to build harbours and other urban development. Beaches, mangroves and salt marshes had been destroyed and replaced with artificial structures. Much of this was concrete, which has a high pH and is very smooth, with none of the nooks and crannies that give new marine life a place to hide from predators and offer some protection from crashing waves. The structures also lacked hollows to retain seawater between tides. “So now people have been making concrete surfaces rough, changing the pH, the colour and the surface chemistry, and we are designing all sort of structures,” Louise said. It is amasing to see some of these structures. Instead of smooth concrete, they have pits and crevices, ridges and shade structures, pools and ledges. The success of these interventions varied, but in most cases they increased both the abundance of sea creatures, as well as the variety of species that were found. A good news story indeed. But, warns Louise, it is all small-scale and short-term – and the destruction of coastal ecosystems is continuing. In Malaysia, for instance, they are building artificial islands that will house thousands of people, but will have a huge impact on the coastal ecosystem. And right in Knysna, the lagoon’s natural sea grass –crucial for the health of the estuary – is disappearing because of human activity. This sea grass is almost like the “engine” of the estuary. Said Louise: “There will be 11 billion people by 2100. We have to learn how to live with that, and not just to take, but also to give back, for the mutual benefit of humans and the environment.” We can start by keeping a watchful eye on coastal developments along the Garden Route, especially those in the estuaries. As they say: Think global, act local.
