OPATM-BFM is an off-line three-dimensional coupled eco-hydrodynamic simulation model used for biogeochemical and ecosystem-level predictions. This paper presents the first results of research activities devoted to the adaptation of the parallel OPATM-BFM application for an efficient usage in modern Grid-based e-Infrastructures. For the application performance on standard Grid architectures providing generic clusters of workstations, such results are important. We propose a message-passing analysis technique for communication-intensive parallel applications based on a preliminary application run analysis. This technique was successfully used for the OPATM-BFM application and allowed us to identify several optimization proposals for the current realization of the communication pattern. As the suggested improvements are quite generic, they can be potentially useful for other parallel scientific applications.