Chapter 05: Vulnerability of marine microbes on the Great Barrier Reef to climate change

Abstract

Global climate change will have a direct effect on the Great Barrier Reef (GBR) as discussed in previous and subsequent chapters. The primary effect of climate change will be a 1 to 3°C increase in global sea surface temperature along with sea level rises as predicted by Intergovernmental Panel on Climate Change (IPCC) models. Other associated effects include increased acidity and increased terrestrial inputs. The effects of climate change will have a significant impact on marine microbes, potentially altering microbial diversity, function and community dynamics. Although microbes constitute by far the largest diversity and biomass of all marine organisms, they are often ignored in discussions about the impacts of climate change. This is despite the fact that the vast microbial life on our planet plays a central role in either accentuating or mitigating the effects of climate change. Since microbes are central to the global cycles (including carbon, nitrogen and trace gases), changes to temperature, nutrient availability and environmental pH will have major impacts on microbial processes central to the climate debate. This chapter will discuss the exposure, sensitivity and impacts of climate change on marine microbes at global, regional and local scales, providing examples of observed impacts in marine ecosystems. In doing so, the adaptive capacity and vulnerability of marine microbes to climate change will be assessed. The background provided in this chapter emphasises the importance of marine microbes and outlines why they require greater appreciation in research effort and consideration in predictive climate models.