The extraordinary resilience of Great Barrier Reef corals, and problems with policy science

[Extract] The Great Barrier Reef is often used to show the imminent crisis we are supposedly facing from climate change. It is photogenic, the water sparkles blue, the fish and corals are beautiful and delicate, and most who see it - particularly marine biologists - fall in love with it. It is abhorrent to even contemplate that it could be destroyed or damaged by humanity. The claimed imminent peril faced by the Great Barrier Reef has captured the public's imagination. When then US president Barack Obama visited Australia, he remarked that he wanted global action on climate change, so that maybe his daughters would have a changed to see the Great Barrier Reef. A visiting architect to my university revealed that his daughter, on discussing the latest reef bleaching event at school, came home depressed that she would probably never be able to see the Great Barrier Reef. Most of the world's population seems to have been persuaded that it has no more than a few years left. There is no doubt that every decade or so, abnormally high seawater temperatures can cause corals to bleach (Marshall & Schuttenberg 2006). Bleaching is when the coral expels the symbiotic algae (zooxanthellae) which normally live inside an individual coral polyp. The polyps are the animals, generally a few millimetres across, that make the calcium carbonate structure of the coral. Thousands or even millions of polyps make up an indificual coral. The symbiotic algae live inside the polyp and make energy from sunlight; they share this energy with the polyp in exchange for a comfortable environment. However, when the water gets much hotte than normal, something goes wrong with the symbionts and they effectively become poisonous to the polyp. The polyp expels the symbionts and - because it is the symbionts that give the polyp its colour - the coral turns white. Without the symbionts, the polyp will run out of energy and die within a few weeks or months, unless it takes on more symbionts that float around naturally in the water surrounding the coral. The ghastly white skeletons of bleached coral, particularly when seen on a massive scale, make graphic and compelling images to demonstrate the perils of climate change. The fact that this only happens when the water gets much hotter than normal makes it a plausible hypothesis that coral bleaching is caused by anthropogenic climate change. It is also often claimed by scientists that mass bleaching has only occurred since the 1970s, and that it is a recent phenomenon that did not occur 100 years ago when the water temperature of the Great Barrier Reef was 0.5°°C to 1.0C degrees cooler (Hughes 2016). Despite this apparently plausible hypothesis, it will be argued in this chapter that there is perhaps no ecosystem on Earth better able to cope with rising temperatures than the Great Barrier Reef. Irrespective of one's views about the role of carbon dioxide (CO₂) in warming the climate, it is remarkable that the Great Barrier Reef has become the ecosystem, more than almost all others, that isused to illustrate and claim environmental disaster from the modest warming we have seen over the course of the last century

The Role of Physical Processes in Mangrove Environments: manual for the preservation and utilization of mangrove ecosystems

Being a scientific society with a vested interest in the protection and restoration of mangroves and other coastal environments, it is with great pride that The International Society for Mangrove Ecosystems (ISME) provides the foreword to this important new work. In recognising the economic and ecological importance of mangrove forests and ecosystems, we have a responsibility to provide the means to sustainably manage and protect this vital coastal resource for future generations. Edited by three outstanding mangrove experts—Prof. Y. Mazda, Dr. E. Wolanski and Dr. P.V. Ridd—this book targets members of the scientific community who are interested in the preservation and sustainable utilisation of mangrove forests. The book has set itself five principal objectives: 1) To instruct mangrove researchers and engineers in developing countries on the physical processes taking place in the mangrove environment; 2) To encourage students to undertake studies of physical processes in mangrove areas; 3) To make coastal physical researchers recognise the peculiarity of mangrove physics; 4) To show the physical mechanisms that have been solved and need to be solved; and 5) To save research time by providing ready access to scientific articles and papers that appear in diverse media in different countries. As reliable information is fundamental to the long-term health of mangrove ecosystems, ISME believes that this book will provide and contribute to the strengthening of scientific understanding, as well as the development and exchange of essential data and information required for the conservation, restoration and management of mangrove forests. The information developed and provided in the book constitutes a vital new resource for effective decision-making and policy formulation in the sustainable management of all mangrove ecosystems

Continuous in situ monitoring of sediment deposition in shallow benthic environments

Sedimentation is considered the most widespread contemporary, human-induced perturbation on reefs, and yet if the problems associated with its estimation using sediment traps are recognized, there have been few reliable measurements made over time frames relevant to the local organisms. This study describes the design, calibration and testing of an in situ optical backscatter sediment deposition sensor capable of measuring sedimentation over intervals of a few hours. The instrument has been reconfigured from an earlier version to include 15 measurement points instead of one, and to have a more rugose measuring surface with a microtopography similar to a coral. Laboratory tests of the instrument with different sediment types, colours, particle sizes and under different flow regimes gave similar accumulation estimates to SedPods, but lower estimates than sediment traps. At higher flow rates (9--17 cm s−1), the deposition sensor and SedPods gave estimates >10× lower than trap accumulation rates. The instrument was deployed for 39 d in a highly turbid inshore area in the Great Barrier Reef. Sediment deposition varied by several orders of magnitude, occurring in either a relatively uniform (constant) pattern or a pulsed pattern characterized by short-term (4--6 h) periods of `enhanced' deposition, occurring daily or twice daily and modulated by the tidal phase. For the whole deployment, which included several very high wind events and suspended sediment concentrations (SSCs) >100 mg L−1, deposition rates averaged 19 ± 16 mg cm−2 d−1. For the first half of the deployment, where SSCs varied from <1 to 28 mg L−1 which is more typical for the study area, the deposition rate averaged only 8 ± 5 mg cm−2 d−1. The capacity to measure sedimentation rates over a few hours is discussed in terms of examining the risk from sediment deposition associated with catchment run-off, natural wind/wave events and dredging activities

Evaluation of a new airborne microwave remote sensing radiometer by measuring the salinity gradients across the shelf of the Great Barrier Reef lagoon

Over the last ten years, some operational airborne remote sensing systems have become available for mapping surface salinity over large areas in near real time. A new dual-polarized Polarimetric L-band Multibeam Radiometer (PLMR) has been developed to improve accuracy and precision when compared with previous instrument generations. This paper reports on the first field evaluation of the performance of the PLMR by measuring salinity gradients in the central Great Barrier Reef. Before calibration, the raw salinity values of the PLMR and conductivity-temperature-depth (CTD) differed by 3-6 psu. The calibration, which uses in situ salinity data to remove long-term drifts in the PLMR as well as environmental effects such as surface roughness and radiation from the sky and atmosphere, was carried out by equating the means of the PLMR and CTD salinity data over a subsection of the transect, after which 85% of the salinity values between the PLMR and CTD are within 0.1 psu along the complete transect. From offshore to inshore across the shelf, the PLMR shows an average cross-shelf salinity increase of about 0.4 psu and a decrease of 2 psu over the inshore 20 km at -19deg S (around Townsville) and -18deg S (around Lucinda), respectively. The average cross-shelf salinity increase was 0.3 psu for the offshore 100 km over all transects. These results are consistent with the in situ CTD results. This survey shows that PLMR provided an effective method of rapidly measuring the surface salinity in near real time when a calibration could be made

Association of gene expression with sequential proliferation, differentiation and tumor formation in murine skin.

Differential gene expression in two established initiation and promotion skin carcinogenesis models during promo-tion and tumor formation was determined by microarray technology with the purpose of distinguishing the genes more associated with neoplastic transformation from those linked with proliferation and differentiation. The first model utilized dimethylbenz[a]anthracene initiation and 12-O-tetradecanoylphorbol 13-acetate (TPA) promotion in the FVB/N mouse, and the second TPA promotion of the Tg.Ac mouse, which is endogenously initiated by virtue of an activated Ha-ras transgene. Comparison of gene expression profiles across the two models identified genes whose altered expression was associated with papilloma formation rather than TPA-induced proliferation and differentiation. DMBA suppressed TPA-induced dif-ferentiation which allowed identification of those genes associated more specifically with differentiation rather than proliferation. EASE (Expression Analysis Systemic Explorer) indicated a correlation between muscle-associated genes and skin differentiation, whereas genes involved with protein biosynthesis were strongly correlated with proliferation. For verification the altered expression of selected genes were confirmed by RT–PCR; Carbonic anhydrase 2, Thioredoxin 1 and Glutathione S-transferase omega 1 associated with papilloma formation and Enolase 3, Cystatin b and Filaggrin associated with TPA-induced proliferation and differentiation. In situ analysis located the papillomas Glutathione S-transferase omega 1 expres-sion to the proliferating areas of the papillomas. Thus we have identified profiles of differential gene expression associated with the tumorigenesis and promotion stages for skin carcinogenesis in the mouse

DeepWeeds: a multiclass weed species image dataset for deep learning

Robotic weed control has seen increased research of late with its potential for boosting productivity in agriculture. Majority of works focus on developing robotics for croplands, ignoring the weed management problems facing rangeland stock farmers. perhaps the greatest obstacle to widespread uptake of robotic weed control is the robust classification of weed species in their natural environment. the unparalleled successes of deep learning make it an ideal candidate for recognising various weed species in the complex rangeland environment. This work contributes the first large, public, multiclass image dataset of weed species from the Australian rangelands; allowing for the development of robust classification methods to make robotic weed control viable. The DeepWeeds dataset consists of 17,509 labelled images of eight nationally significant weed species native to eight locations across northern Australia. This paper presents a baseline for classification performance on the dataset using the benchmark deep learning models, Inception-v3 and ResNet-50. These models achieved an average classification accuracy of 95.1% and 95.7%, respectively. We also demonstrate real time performance of the ResNet-50 architecture, with an average inference time of 53.4 ms per image. These strong results bode well for future field implementation of robotic weed control methods in the Australian rangelands