Effects of climate change on Shark Bay microbial mats

Microbial mat ecosystems in Shark Bay Australia are under varied levels of stress as a result of hypersalinity, temperature, and desiccation. In addition, this region is sometimes subjected to the extreme effects of cyclones. Despite the wide range of potential pathways and mechanisms for environmental adaptation evident in Shark Bay mat microbiomes, to date there are no studies to evaluate how resilient and/or susceptible these microbial mat communities in the face of natural disturbances such as storms and cyclones. The impact of extreme stressors on microbial communities and critical pathways in threatened mat systems in Shark Bay are unknown and critical to ascertain before any irreversible ecosystem tipping points are reached. Cyclone Olwyn, a Category 3 cyclone hit the coastline of Western Australia, including Shark Bay, on March 2015. During the cyclone, heavy rainfall of up to 142 mm in 24 hours, and a maximum wind gust up to 180 km/h was recorded.

The aim of the present investigation, lead by honours student Max Reinold, is to compare at the taxonomic and functional metagenomic level specific mats in Shark Bay pre-cylcone (2013), with the same mats post-cyclone in successive years (2015, 2017, 2019), to determine how Shark Bay microbial mats respond at the community level to the environmental disturbances of a cyclone, and whether it could potentially alter microbial functions and nutrient cycling.

Flight path of Cyclone Olwyn along the coast of Western Australia