• Energy Research

The microbialization of coral reefs predicts that microbial oxygen consumption will cause reef deoxygenation. Here we tested this hypothesis by analyzing reef microbial and primary producer oxygen metabolisms. Metagenomic data and in vitro incubations of bacteria with primary producer exudates showed that fleshy algae stimulate incomplete carbon oxidation metabolisms in heterotrophic bacteria. These metabolisms lead to increased cell sizes and abundances, resulting in bacteria consuming 10 times more oxygen than in coral incubations. Experiments probing the dissolved and gaseous oxygen with primary producers and bacteria together indicated the loss of oxygen through ebullition caused by heterogenous nucleation on algae surfaces. A model incorporating experimental production and loss rates predicted that microbes and ebullition can cause the loss of up to 67% of gross benthic oxygen production. This study indicates that microbial respiration and ebullition are increasingly relevant to reef deoxygenation as reefs become dominated by fleshy algae.

In this paper, we describe two new methods to address the model type selection problem (MTSP) based on modifications of the coral reefs optimisation algorithm (CRO). The effectiveness of these novel approaches is subsequently illustrated in a problem of energy demand estimation in Spain. First, we describe how coral species can be defined in the CRO algorithm, so each specie defines a competing model for the MTSP. Second, we propose another method to solve MTSPs by modifying the original CRO with a substrate layer, so that the different models considered can be encoded similarly. This second method to solve the MTSP simplifies the application of the CRO operators. Finally, we evaluate the performance of the two CRO-based algorithms by solving a MTSP consisting of the prediction of future energy demand from macro-economic data in Spain as a case study.