Protecting marine life in urban waters

October 06, 2021

As the Government launches a call for research proposals under the new Marine Climate Change Science programme in November 2021, we take a look at the outcomes of our work from the earlier Marine Science Research and Development Programme which now draws to a close.

Biological Sciences’ Assoc Prof Peter Alan TODD’s project – ecologically engineering Singapore’s seawalls to enhance biodiversity – was one of two anchor projects under this programme. 

As an ecologist and scuba diver,  it was “almost inevitable” that Assoc Prof Todd, who is also the Director of the interdisciplinary Environmental Studies programme under NUS’ College of Humanities and Sciences (CHS), ended up studying coral reefs and coastal systems.

He said, “As natural coastlines are globally being replaced by human-made structures, a concerted and cohesive effort is required to conserve shoreline biodiversity and maintain ecosystem services.”

With this in mind, his team set out to create future-ready seawalls that host a diverse array of native species that bring positive impacts to neighbouring habitats and enhance ecosystem resilience.

This work is both timely and important. By the next decade, approximately three quarters of the world’s population will reside in coastal zones. In addition, sea-level rise and more intense storms have led to an urgent need for shoreline protection. As a result, man-made coastal defences such as seawalls are quickly becoming the primary means of mitigating the risks of flooding and erosion.

However, seawalls differ from natural shores in fundamental ways. They are usually very steep, increasing the effects of wave impact and compressing the intertidal zone. Seawalls have few microhabitats – such as pits, rock pools, overhangs, and crevices – and little structural complexity. They are frequently made from materials that may not be well-suited for colonisation and/or exhibit thermal properties that result in unfavourably high temperatures when the tide is down.

As these structures are permanent, there is now substantial interest in maximising their ecological value. Designing urban infrastructure in a manner congruent with ecological principles is known as ecological engineering, and this concept lies at the heart of this project. 

Assoc Prof Todd added, “We approached the challenge of how seawalls can support an abundant and diverse array of species through a unique synthesis of ecology, materials science, microbiology and fluid mechanics.”

Marine tiles at Changi Bay – Photo credit Stephen Caffyn

NUS will be working with HDB (Housing and Development Board) to install more than 3,000 of these “green” seawall tiles around Pulau Tekong to enhance its coastal marine biodiversity.

Source: https://www.straitstimes.com/singapore/environment/new-marine-climate-science-programme-in-spore-to-call-for-proposals-in