Shoalwater Bay fringing reef resource assessment

The Great Barrier Reef Marine Park Authority is involved in preparing management strategies for the whole Shoalwater Bay area, as well as zoning plans for the Byfield Coast area, immediately east of Shoalwater Bay. They have found a lack of information on the state of the fringing reefs that aerial photographs suggest are present around many of the shoals and islands in this area

Upwelling linked to warm summers and bleaching on the Great Barrier Reef

We investigate a range of indices to quantify upwelling on the central Great Barrier Reef (GBR), Australia, so that environmental and biological relationships associated with upwelling in this area can be explored. We show that "Upwelling days" (the number of days of upwelling) and diurnal variation in subsurface temperature (maximum-minimum, 20-m depth) are satisfactory metrics to describe the duration and intensity of upwelling events, respectively. We use these to examine key characteristics of shelf-break upwelling in the central GBR. Our results show, somewhat paradoxically, that although upwelling involves cold water being brought near to the surface, it is linked to positive thermal anomalies on the GBR, both locally and regionally. Summers (December to February) with strongest upwelling occurred during the GBR-wide bleaching events of 1997-1998 and 2001-2002. Upwelling in the GBR is enhanced during doldrums conditions that were a feature of these summers. During these conditions, the poleward-flowing East Australian Current flows faster, lifting the thermocline closer to the surface, spilling more sub-thermocline waters onto the shelf. Doldrums conditions also result in intense local heating, stratification of the water column, and, when severe, coral bleaching. Upwelling intrusions are spatially restricted (central GBR), generally remain subsurface, and are often intermittent, allowing GBR-wide bleaching to occur despite conditions resulting in enhanced upwelling. Intense upwelling events precede anomalous seasonal temperature maxima by up to 2 months and bleaching by 1-3 wk, leading to the prospect of using upwelling activity as a seasonal forecasting index of unusually warm summers and widespread bleaching

Variation in bleaching sensitivity of two coral species across a latitudinal gradient on the Great Barrier Reef: The role of zooxanthellae

The ability of corals to cope with environmental change, such as increased temperature, relies on the physiological mechanisms of acclimatisation and long-term genetic adaptation. We experimentally examined the bleaching sensitivity exhibited by 2 species of coral, Pocillopora damicornis and Turbinaria reniformis, at 3 locations across a latitudinal gradient of almost 6 degrees on the Great Barrier Reef (GBR). Target bleaching temperature was reached by using a ramping rate of 0.2°C/h. We found that the bleaching sensitivity and recovery of both species differed between corals with clade D symbionts and those with clade C. However, in P. damicornis bleaching susceptibility corresponded more strongly with latitude than with zooxanthella type and hence, temperature history, suggesting that local adaptation has occurred. The observed bleaching sensitivity was shown by a decrease in photochemical efficiency (Fv/Fm) in both species of coral. The rate of recovery in T. reniformis was highest in explants containing clade D symbionts. The occurrence of clade D in the northern section of the GBR may reflect a long-term response to high sea water temperatures, while the presence of clade D in low abundance in T. reniformis at Heralds Prong Reef and Percy Island may be a result of recent bleaching events. © Inter-Research 2006

A community change in the algal endosymbionts of a scleractinian coral following a natural bleaching event: field evidence of acclimatization.

The symbiosis between reef-building corals and their algal endosymbionts (zooxanthellae of the genus Symbiodinium) is highly sensitive to temperature stress, which makes coral reefs vulnerable to climate change. Thermal tolerance in corals is known to be substantially linked to the type of zooxanthellae they harbour and, when multiple types are present, the relative abundance of types can be experimentally manipulated to increase the thermal limits of individual corals. Although the potential exists for this to translate into substantial thermal acclimatization of coral communities, to date there is no evidence to show that this takes place under natural conditions. In this study, we show field evidence of a dramatic change in the symbiont community of Acropora millepora, a common and widespread Indo-Pacific hard coral species, after a natural bleaching event in early 2006 in the Keppel Islands (Great Barrier Reef ). Before bleaching, 93.5% (nZ460) of the randomly sampled and tagged colonies predominantly harboured the thermally sensitive Symbiodinium type C2, while the remainder harboured a tolerant Symbiodinium type belonging to clade D or mixtures of C2 and D. After bleaching, 71% of the surviving tagged colonies that were initially C2 predominant changed to D or C1 predominance. Colonies that were originally C2 predominant suffered high mortality (37%) compared with D-predominant colonies (8%). We estimate that just over 18% of the original A. millepora population survived unchanged leaving 29% of the population C2 and 71% D or C1 predominant six months after the bleaching event. This change in the symbiont community structure, while it persists, is likely to have substantially increased the thermal tolerance of this coral population. Understanding the processes that underpin the temporal changes in symbiont communities is key to assessing the acclimatization potential of reef corals

Present Limits to Heat-Adaptability in Corals and Population-Level Responses to Climate Extremes

Climate change scenarios suggest an increase in tropical ocean temperature by 1–3°C by 2099, potentially killing many coral reefs. But Arabian/Persian Gulf corals already exist in this future thermal environment predicted for most tropical reefs and survived severe bleaching in 2010, one of the hottest years on record. Exposure to 33–35°C was on average twice as long as in non-bleaching years. Gulf corals bleached after exposure to temperatures above 34°C for a total of 8 weeks of which 3 weeks were above 35°C. This is more heat than any other corals can survive, providing an insight into the present limits of holobiont adaptation. We show that average temperatures as well as heat-waves in the Gulf have been increasing, that coral population levels will fluctuate strongly, and reef-building capability will be compromised. This, in combination with ocean acidification and significant local threats posed by rampant coastal development puts even these most heat-adapted corals at risk. WWF considers the Gulf ecoregion as “critically endangered”. We argue here that Gulf corals should be considered for assisted migration to the tropical Indo-Pacific. This would have the double benefit of avoiding local extinction of the world's most heat-adapted holobionts while at the same time introducing their genetic information to populations naïve to such extremes, potentially assisting their survival. Thus, the heat-adaptation acquired by Gulf corals over 6 k, could benefit tropical Indo-Pacific corals who have <100 y until they will experience a similarly harsh climate. Population models suggest that the heat-adapted corals could become dominant on tropical reefs within ∼20 years

Who didn't consult the doctor? Understanding sociodemographic factors in relation to health care uptake before suicide

Objective: This study aimed to establish differences between suicide decedents and a reference population across various health care settings.Methods: This population-wide registration study combined death statistics, sociodemographic data and health care data from Statistics Netherlands. From 2010 to 2016, 12,015 suicide cases and a random reference group of 132,504 were included and assigned to one of the three health care settings; mental health (MH) care, primary care or no care. Logistic regression analyses were performed to determine differences in suicide risk factors across settings.Results: In the 1–2 year period before suicide, 52% of the suicide decedents received MH care, 41% received GP care only and 7% received neither. Although sociodemographic factors showed significant differences across settings, the suicide risk profiles were not profoundly distinctive. A decreasing trend in suicide risk across health care settings became apparent for male gender, income level and being in a one-person or one-parent household, whereas for other factors (middle and older age, non-Western migration background, couples without children and people living in more sparsely populated areas), risk of suicide increased when health care setting became more specialized.Limitations: Because of the data structure, 18 months of suicide decedents’ health care use were compared with two years health care use of the reference group, which likely led to an underestimation of the reported differences.Conclusion: Although there are differences between suicide decedents and a reference group across health care settings, these are not sufficiently distinctive to advocat

Development and Validation of Computational Fluid Dynamics Models for Prediction of Heat Transfer and Thermal Microenvironments of Corals

We present Computational Fluid Dynamics (CFD) models of the coupled dynamics of water flow, heat transfer and irradiance in and around corals to predict temperatures experienced by corals. These models were validated against controlled laboratory experiments, under constant and transient irradiance, for hemispherical and branching corals. Our CFD models agree very well with experimental studies. A linear relationship between irradiance and coral surface warming was evident in both the simulation and experimental result agreeing with heat transfer theory. However, CFD models for the steady state simulation produced a better fit to the linear relationship than the experimental data, likely due to experimental error in the empirical measurements. The consistency of our modelling results with experimental observations demonstrates the applicability of CFD simulations, such as the models developed here, to coral bleaching studies. A study of the influence of coral skeletal porosity and skeletal bulk density on surface warming was also undertaken, demonstrating boundary layer behaviour, and interstitial flow magnitude and temperature profiles in coral cross sections. Our models compliment recent studies showing systematic changes in these parameters in some coral colonies and have utility in the prediction of coral bleaching

Long-Term Survival Associated with Direct Oral Feeding Following Minimally Invasive Esophagectomy:Results from a Randomized Controlled Trial (NUTRIENT II)

Advancements in perioperative care have improved postoperative morbidity and recovery after esophagectomy. The direct start of oral intake can also enhance short-term outcomes following minimally invasive Ivor Lewis esophagectomy (MIE-IL). Subsequently, short-term outcomes may affect long-term survival. This planned sub-study of the NUTRIENT II trial, a multicenter randomized controlled trial, investigated the long-term survival of direct versus delayed oral feeding following MIE-IL. The outcomes included 3- and 5-year overall survival (OS) and disease-free survival (DFS), and the influence of complications and caloric intake on OS. After excluding cases of 90-day mortality, 145 participants were analyzed. Of these, 63 patients (43.4%) received direct oral feeding. At 3 years, OS was significantly better in the direct oral feeding group (p = 0.027), but not at 5 years (p = 0.115). Moreover, 5-year DFS was significantly better in the direct oral feeding group (p = 0.047) and a trend towards improved DFS was shown at 3 years (p = 0.079). Postoperative complications and caloric intake on day 5 did not impact OS. The results of this study show a tendency of improved 3-year OS and 5-year DFS, suggesting a potential long-term survival benefit in patients receiving direct oral feeding after esophagectomy. However, the findings should be further explored in larger future trials.</p