The Effects of Climate Change on Hawaii’s Coral Reef Ecosystem Over the Past 20 Years

Abstract

The Hawaiian islands are known for their rich marine biodiversity in coral reef ecosystems. However, in the last 20 years, changes in sea surface temperatures, sea levels, carbon dioxide levels, and ocean pH have severely impacted these reef ecosystems. Hawaiian corals can experience heat stress with temperatures as little as 1-2 °C above the average and thermal stress events were prevalent from 2014-2017, causing bleaching and increasing mortality. The increase in sea level in Hawaiian marine ecosystems has caused reefs to “drown” from the lack of sufficient sunlight and thus suffer from bleaching. Coral disease is linked with high temperatures, seen through the common reef-building coral disease white syndrome. Invasive species outbreaks, with Acanthaster planci as an example, are also correlated with changes in the climate and reef communities. With the loss of coral, there have been consequences on marine biodiversity in Hawaiian reef ecosystems. Specifically, the three most native coral genera, porites, montipora, and pocillopora, which are the most important species to the reefs, have been declining in population. As a result, higher threat statuses have been observed among turtles, reef fish, and marine mammals that are reliant on their coral reef ecosystems for protection and food sources.