Development of a Biogeochemical and Carbon Model Related to Ocean Acidification Indices with an Operational Ocean Model Product in the North Western Pacific

Yasumasa Miyazawa,Tomohiko Tsunoda,Miho Ishizu,Xinyu Guo

doi:10.3390/su11092677

Abstract

We developed a biogeochemical and carbon model (JCOPE_EC) coupled with an operational ocean model for the North Western Pacific. JCOPE_EC represents ocean acidification indices on the background of the risks due to ocean acidification and our model experiences. It is an off-line tracer model driven by a high-resolution regional ocean general circulation model (JCOPE2M). The results showed that the model adequately reproduced the general patterns in the observed data, including the seasonal variability of chlorophyll-a, dissolved inorganic nitrogen/phosphorus, dissolved inorganic carbon, and total alkalinity. We provide an overview of this system and the results of the model validation based on the available observed data. Sensitivity analysis using fixed values for temperature, salinity, dissolved inorganic carbon and total alkalinity helped us identify which variables contributed most to seasonal variations in the ocean acidification indices, pH and Ωarg. The seasonal variation in the pHinsitu was governed mainly by balances of the change in temperature and dissolved inorganic carbon. The seasonal increase in Ωarg from winter to summer was governed mainly by dissolved inorganic carbon levels.

Highlights

Ocean acidification poses a serious risk to marine organisms and ecosystems, including finfish and coral reefs in subtropical regions, and species or groups of organisms in polar regions [1,2,3,4,5]
To improve our insights into the drivers of ocean acidification, we aimed to develop the Japan Coastal Ocean Predictability Experiment (JCOPE) further to incorporate a new marine ecosystem and carbon cycle model, driven by the physical processes represented by the JCOPE2M model outputs [37]
We found that the first version of the created ALK data was significantly different from the ALK observed data obtained for the Japan Sea for the period 1997–2017, downloaded from the Japan Meteorological Agency (JMA) website, so we replaced the ALK data for the Japan Sea with the JMA

Summary

Introduction

Ocean acidification poses a serious risk to marine organisms and ecosystems, including finfish and coral reefs in subtropical regions, and species or groups of organisms in polar regions [1,2,3,4,5]. The effects of ocean acidity have previously been reported and the effects of acidification are predicted to increase, with great risks to marine organisms [2,4,5,6,7]. The global economic loss of organisms from ocean acidification has been estimated at $24 billion, $0.7 billion, $37 billion, $65 billion, and $30–375 billion for molluscs, echinoderms, crustaceans, finfish, and corals, respectively. Some organisms including molluscs and echinoderms may become locally extinct, and corals will be damaged by the combined effects of global warming and ocean acidification, which will reduce calcification, increase bio-erosion, and have synergistic effects [8]. All organisms except echinoderms could be seriously affected, and substantial economic losses are likely [8]. These issues can no longer be ignored, and urgent action is necessary

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Results

Discussion

Conclusion