Data from: The rainbow connection: the case for including substrate colour in the ‘eco-engineering’ of marine constructions

The urbanisation of the world’s coastlines is replacing diverse natural
substrates with grey concrete. The changing shoreline colourscape may
potentially influence colonisation of marine surfaces, by influencing
settlement patterns and predator-prey interactions, but is overlooked in
the design of marine structures for ecological co-benefits. This study
assessed how manipulating the colour of concrete influenced benthic
community development on intertidal seawalls in Sydney Harbour, Australia,
when fin-fish predators had access to panels or were excluded by cages.
Four colours were compared at high and low intertidal elevations of two
sites: grey (the colour of concrete); red and yellow (the colours of
natural Sydney sandstone rock) and green (the colour of algal biofilms).
Red substrate developed distinct ecological communities compared to
yellow, green and grey substrates, with many taxa positively associated
with red. Effects of colour were greater in the low than the high
intertidal, reflecting the greater number of colonising species on which
colour could act.  Effects were generally similar across caged
and open surfaces, consistent with effects of colour on settlement
preferences rather than predation effects. Contrary to the hypothesis that
effects would diminish through time with declining bare space with which
colonists could interact, the colour effect persisted for the duration of
the 12-month study.  Synthesis and applications. Our results show
that in the low intertidal, colour can shape sessile community assembly on
concrete surfaces over time scales of at least 12 months. Consequently,
alongside the habitat complexity and material type of marine built
structures, colour warrants consideration in the development of
eco-friendly designs. The colour of marine built structures is easily
manipulated, for example through the addition of non-toxic oxides to
concrete as done here.