Influence of the Intrinsic Characteristics of Cementitious Materials on Biofouling in the Marine Environment

Abstract

Coastal marine ecosystems provide essential benefits and services to humanity, but many are rapidly degrading. Human activities are leading to significant land take along coastlines and to major changes in ecosystems. Ecological engineering tools capable of promoting large-scale restoration of coastal ecosystems are needed today in the face of intensifying climatic stress and human activities. Concrete is one of the materials most commonly used in the construction of coastal and marine infrastructure. Immersed in seawater, concretes are rapidly colonized by microorganisms and macroorganisms. Surface colonization and subsequent biofilm and biofouling formation provide numerous advantages to these organisms and support critical ecological and biogeochemical functions in the changing marine environment. The new challenge of the 21st century is to develop innovative concretes that, in addition to their usual properties, provide improved bioreceptivity in order to enhance marine biodiversity. The aim of this study is to master and clarify the intrinsic parameters that influence the bioreceptivity (biocolonization) of cementitious materials in the marine environment. By coupling biofilm (culture-based methods) and biofouling (image-analysis-based method and wet-/dry-weight biomass measurement) quantification techniques, this study showed that the application of a curing compound to the concrete surface reduced the biocolonization of cementitious materials in seawater, whereas green formwork oil had the opposite effect. This study also found that certain surface conditions (faceted and patterned surface, rough surface) promote the bacterial and macroorganism colonization of cementitious materials. Among the parameters examined, surface roughness proved to be the factor that promotes biocolonization most effectively. These results could be taken up in future recommendations to enable engineers to eco-design more eco-friendly marine infrastructure and develop green-engineering projects.

Development of laboratory tests to measure the growth kinetic of micro-algae of concrete in marine environment and comparison to in-situ experiments

“…Up to now, the main development in reef was focused on its design and on its capacity to supply habitat for different fish and animal size [11]. More recent studies showed that surface bioreceptivity of concrete can be obtained and enhanced by slight modification of concrete composition and surface texture for instance: this was confirmed by laboratory studies [12] but also in-situ measurements [13]. The development of a laboratory test for the bio-receptivity of concrete is crucial: this allows to screen a very large range of concrete composition and surface texture in controlled conditions without any extra cost required to carry out colonization follow up in marine environment.…”

Influence of Tourism Disturbance on Soil Microbial Community Structure in Dawei Mountain National Forest Park

“…As an important part of the ecosystem, soil is easily degraded by a series of manmade activities such as tourism development activities, trampling, garbage discharge, etc., which affects the growth and development of vegetation and may eventually lead to the degradation of soil and vegetation. It affects the entire tourism environment and is not conducive to the sustainable development of eco-tourism [39]. The quality of soil conditions has an important impact on the survival of the soil ecosystem, the plant ecosystem that grows on it, its animal communities, and soil microbial communities, while it also plays an important role in the health and stability of the tourism ecosystem.…”

How to Improve the Bioreceptivity of Concrete Infrastructure Used in Marine Ecosystems? Literature Review for Mechanisms, Key Factors, and Colonization Effects

“…As the colonization of cementitious material by microorganisms is an essential step for the adhesion of other organisms (Mieszkin, Callow, and Callow, 2013;Rajitha, Nancharaiah, and Venugopalan, 2020;Salta et al, 2013), the aim is to favor this colonization in order to reduce the ecological impact of the structure and consequently increase biodiversity, without impacting the structure's strength and durability. Then, additional studies are necessary to determine the different factors that can influence the colonization of cementitious materials in the marine environment, but the main parameters seem to be the water pH, the materials chemical composition, and surface roughness or topography (Grosseau et al, 2015;Hayek et al, 2020aHayek et al, , 2021McManus et al, 2018;Miller et al, 2009Miller et al, , 2012.…”