Australia: The Land Where Time Began

A biography of the Australian continent 

Northwest Australia – Evidence for Synchrony of Marine and Terrestrial Ecosystems that is Driven by Climate

It is difficult to predict the effects of climate change for many marine species as not much is known about their response to climate change in the past. A variable that integrates multiple physical and biological factors, the long-term chronologies of growth, have become available for several marine taxa. These have allowed a search for synchrony in growth that is driven by climate across multiple taxa and ecosystems, identifying the key processes that drive biological responses on very large spatial scales. Ong et al. hypothesised that in northwest Australia, which is a region that is predicted to be strongly influenced by climate change, the El Niño-Southern Oscillation (ENSO) phenomenon would be an important factor that influences the growth patterns of organisms in terrestrial as well as marine environments. Ong et al. analysed existing growth chronologies of the marine fish Lutjanus argentimaculatus, the coral Porites spp. And the tree Callitris columellaris and they developed a new chronology for another marine fish, Lethrinus nebulosus. Evidence of ENSO-driven synchrony in growth among all 4 taxa at interannual time scales, was shown by principal components analysis and linear model selection, which was the first such result for the Southern Hemisphere. The annual growth of trees, fishes and corals are all influenced by rainfall, sea surface temperature and the salinities of the surface water, which are linked to the ENSO system. The 4 taxa had negative relationships with the Niño-4 index, which is a measure of ENSO status, and during strong La Niña years, positive growth patterns occurring. Ong et al. suggest that it is implied by this finding that changes in the future in the strength and frequency of ENSO events are likely to have major consequences for marine and terrestrial taxa. Ong et al. suggest that as a result of the strong similarities in growth patterns of fish and trees, tree ring chronologies may possibly be used, which cover a wider span of time than fish, to increase understanding of historical and future responses of fish populations to climate variation.

1. Ong, J. J. L., A. N. Rountrey, J. Zinke, J. J. Meeuwig, P. F. Grierson, A. J. O'Donnell, S. J. Newman, J. M. Lough, M. Trougan and M. G. Meekan (2016). "Evidence for climate-driven synchrony of marine and terrestrial ecosystems in northwest Australia." Global Change Biology 22(8): 2776-2786.