Benthic community establishment on different concrete mixtures introduced to a German deep-water port

Lydia R Becker,Ingrid Kröncke,Kai Bischof,Andreas Ehrenberg,Volkert Feldrappe

doi:10.1186/s10152-021-00550-3

Abstract

Concrete is a widely used building material in coastal constructions worldwide. However, limited natural resources used in the production process, as well as high CO2-emission due to the calcination process of limestone and the thermal energy demand for Portland cement clinker production, raise the demand for alternative constituents. Alternative mixture types should be environmentally friendly and, at best, mimic natural hard substrates. Here five different concrete mixtures, containing different cements (Portland cement and blast furnace cements) and aggregates (sand, gravel, iron ore and metallurgical slags) were made. Three replicate cubes (15 × 15 × 15 cm) of each type were then deployed in a German deep-water Port, the JadeWeserPort, to study benthic community establishment after one year. Results are compared to a similar experiment conducted in a natural hard ground environment (Helgoland Island, Germany). Results indicate marked differences in settled communities in the Port site compared to natural environments. At the Port site community composition did not differ with the concrete mixtures. Surface orientation of the cubes (front/top/back) revealed significant differences in species abundances and compositions. Cubes hold more neobiota in the Port site than in natural hard ground environments. Implications for the usage of new concrete mixtures are discussed.

Highlights

Coastal infrastructures do not function as surrogate for natural marine habitats
In order to compare succession on natural and artificial structures, we report here on a settlement experiment on concrete cubes made of the same mixtures and deployed in the same time span as in Becker et al [44], but in a completely different environment; the JadeWeserPort as an example of a recently erected artificial habitat (Wilhelmshaven, Germany)
Taking the JadeWeserPort as a representative example of a recently established artificial infrastructure with high anthropogenic impact, this study focuses on the following questions: (1) Are there differences in the benthic communities settled on different mixture types after one year of deployment in an anthropogenically influenced area?

Summary

Introduction

Even though artificial structures act as key anthropogenic drivers of environmental change to coastal habitats worldwide [1], ecological consequences of their introduction to the marine environment, to date, have received relatively little attention [2,3,4,5,6,7,8]. While natural habitats slope gently or have heterogeneous topography, artificial constructions frequently provide vertical habitat [6, 15,16,17]. This can lead to increased densities of certain species and to an increasing strength of interspecific interactions [1, 18]. Observation of the community establishment on newly introduced artificial structures

Methods

Results

Conclusion