Climate changes our shelf and coral

Climate change has been one of the most spotlighted issues in Geoscience. Every part of the Earth systems, including oceanic currents, seabed morphology and coral reefs on it, is influenced by this global climate change. Although the majority of marine lives thrives on the continental shelf seabed, forecasting the fate of the shallow sea environment has been difficult due to lack of observational data. Salles and his colleagues suggested a new model for the change of seabed on the Australian continental shelf by the global climate change.

The low-latitude continental shelf fosters a great diversity of marine organisms, especially when a large scale of coral reef has been developed on it. A constant supply of nutrient-rich sediment, interaction with water currents and fickle weather and climate conditions influence in the seabed environments in terms of both morphology and ecology.

The Australian continent is surrounded by broad continental shelves on which gigantic coral reef systems have been developed. Given the shelf rich in coral reefs is a shelter for a large scale of marine ecosystem, the warm Australian coast became one of the most climate-change sensitive zone around the world. The changes in Australian continental shelf are important to estimate the effect of global climate change.

Salles et al. try to overcome the scarce seabed and coral reef data using accumulated ocean currents data and modeling. For this model, authors select Australia as research site and collect physical current data.

These authors have taken three possible climate scenarios into account: a stationary, low-energy and high-energy scenarios. A stationary scenario represents the continuous climate conditions of current state. The high- and low-energy scenarios presume the highest and the lowest rainfalls, analogous to the La Nina and El Nino years, respectively.

Generally erosion is stronger than accretion in shallow shelf, but accretion is stronger in the rest shelf. The stationary scenario produces totally accretion is superior to erosion. In the high-energy scenario, stronger wave and current disturb sediment settle, produces the strongest and broadest erosion and increasing mobility. For the low-energy scenario, both erosion and accretion are weaker.

In figure 1, seabed carbonate is fretted in high-energy scenario, which means the coral reef is damaged in the high-energy scenario.

Advanced model can be published, because of lack of observational data and uncertainty of climate change. But this model proves that climate change have a bad influence on growth and subsistence of coral and degree of that mechanism first around the world.