Sven Uthicke (AIMS), Katharina Fabricius, Andrew Negri, Sam Noonan, Florita Flores, Frances Patel, Michelle Liddy, Niko Vogel, Melissa Rocker, Yan Xiang Ow, Martinda de Freitas-Prazeres, Adriana Humanes Schumann; Experimental and field investigations of combined water quality and climate effects on corals and other reef organisms; Thursday 9th May 2013.
Zhao J, Pandolfi J, Clark T, Done T, Smithers S, Lewis S, McCulloch M, Roff G, McCook L, Welsh K, Feng Y, Rodriguez-Ramirez A, Liu E, Markham H, Leonard N, Lepore M, Prazeres M, Butler I, D'Olivo J, Rogers E, Ryan E; Historical changes on the GBR: looking to the past to manage the future; Thursday 9th May 2013.
Prof. Scott Bainbridge (AIMS) and Dr. Scarla Weeks (UQ)
While the 2013-14 summer was cool, satellite data show that conditions have been developing that could lead to a warmer summer in 2014-15. Neutral ENSO conditions continued in the Pacific through January to May but the eastward propagation of an intense wave of warm water, known as a Kelvin Wave, across the tropical Pacific Ocean over the past several months, has led to a 70-80% probability of transition to El Niño conditions by spring 2014.
If the ocean systems move from neutral to strong El Niño conditions, then we can expect the weather patterns to change to bring warmer dryer summers. In this case there is the potential for a warmer than normal 2014-15 summer with associated increase in coral bleaching risk. The last big El Niño event was in 1997-98, which resulted in worldwide high summer ocean temperatures and resulted in a global coral bleaching event. While the systems that drive this are still forming and what they will do is still uncertain, it is important to understand that cool summers, which protect corals, are the exception not the norm.
The ocean data from Thursday and Masig (Yorke) Islands showed that conditions for the 2013-14 summer were generally cooler than the long term average. The ocean temperature data for Thursday Island (Graph One) show the daily average temperatures as a red line on top of the long-term (15 years of data) average temperature (purple line) and the limits of normal temperatures (blue line – maximums, green line minimums).
Graph One. Ocean temperature data from Thursday Island (red line) plotted against the long-term mean (purple line) and the upper (blue) and lower (green) limits of the normal temperature range.
The data shows that ocean temperatures were close to normal for most of the early summer period with just a few hot spells in early December and again in early January. Temperatures then cooled with cooler than average temperatures during early February and cool conditions lasting until early April. The rainfall data for Thursday Island little early rain with a late monsoon arriving in mid-January and the first significant falls in late January, the peak being 170mm on 30 January. Masig Island had significantly less rain than Thursday Island with only 730mm falling for the period versus 1,840mm for Thursday Island, but the rain was more evenly spread with some early summer rain in November and early December.
Satellite data from NASA’s Moderate Resolution Imaging Spectroradiometer (MODIS) confirms the generally cool conditions with the image from January showing a few minor areas warmer than the average and no overall ‘hot-spots’, that is areas with above average temperatures. What data from a range of satellites does show is the occurrence of widespread hot-spots over the central and eastern Pacific with large areas of warmer than normal ocean water both at the surface and below.
This is being driven by the equatorially-trapped Kelvin Wave that reached the west coast of South America in April and is shown by changes in ocean height across the Pacific (below). This type of pattern is characteristic of the early stages of an El-Niño pattern with a 70-80% chance that the El-Niño pattern will form by the end of the year. If the system moves from its current neutral conditions to El-Niño conditions then we can expect, from previous events, to see warmer dryer summers and with this an increased risk of coral bleaching.
Figure 2. Data from the Jason-2 satellite showing changes in ocean height (sea surface height anomalies) across the tropical Pacific Ocean due to the eastward propagation of an intense wave of warm water, known as a Kelvin Wave. The leading edge of the equatorially-trapped Kelvin Wave reached the west coast of South America in April and is shown by positive changes in ocean height (red-white), resulting in positive temperature anomalies over much of the eastern tropical Pacific. Negative surface height anomalies (black-pink-blue) are evident in the western tropical Pacific, associated with cooler-than-normal ocean temperatures. This type of pattern is characteristic of the early stages of an El-Niño pattern.
While this event is still forming (and may yet dissipate) and we don’t know the potential impact at this stage, there is a need to increase our awareness of potential high temperature events, and the impacts these may have, for this coming summer and potentially those that follow.
Allan Dale (JCU); Transforming the Wet Tropics landscape: Can we create an ecosystem services economy; Thursday 6th November.
Ben Reid (JCU), Amélie Augé, Owen Woodberry, Bob Pressey, Jon Brodie, Allan Dale, Hugh Yorkston, Ann E. Nicholson; Understanding the cumulative impacts of coastal development on marine ecosystems: Land-use change scenarios and Bayesian networks; Wednesday 5th November.
Brad Congdon (JCU); Critical seabird foraging locations and trophic relationships for the GBR; Thursday 6th November.
Catherine Collier (JCU); Thresholds and indicators of declining water quality as tools for tropical seagrass monitoring and management; Thursday 6th November.
Cathy Dichmont (CSIRO); Local people influencing regional coastal management: Decision support tools and experinces through case studies; 5th November 2014.
Conrad Hoskin (JCU); The importance of peripheral areas of the Wet Tropics for conversation of biodiversity; Thursday 6th November.
Damien Burrows (JCU), Norm Duke (JCU), Mark Geyle (TSRA); Mangrove, freshwater and coastal wetlands; Wednesday 5th November.