Ocean warming and acidification threaten the future growth of coral reefs. This is because the calcifying coral reef taxa that construct the calcium carbonate frameworks and cement the reef together ...are highly sensitive to ocean warming and acidification. However, the global-scale effects of ocean warming and acidification on rates of coral reef net carbonate production remain poorly constrained despite a wealth of studies assessing their effects on the calcification of individual organisms. Here, we present global estimates of projected future changes in coral reef net carbonate production under ocean warming and acidification. We apply a meta-analysis of responses of coral reef taxa calcification and bioerosion rates to predicted changes in coral cover driven by climate change to estimate the net carbonate production rates of 183 reefs worldwide by 2050 and 2100. We forecast mean global reef net carbonate production under representative concentration pathways (RCP) 2.6, 4.5, and 8.5 will decline by 76, 149, and 156%, respectively, by 2100. While 63% of reefs are projected to continue to accrete by 2100 under RCP2.6, 94% will be eroding by 2050 under RCP8.5, and no reefs will continue to accrete at rates matching projected sea level rise under RCP4.5 or 8.5 by 2100. Projected reduced coral cover due to bleaching events predominately drives these declines rather than the direct physiological impacts of ocean warming and acidification on calcification or bioerosion. Presently degraded reefs were also more sensitive in our analysis. These findings highlight the low likelihood that the world's coral reefs will maintain their functional roles without near-term stabilization of atmospheric CO
emissions.
•Used soft system dynamics to study risk communication during health risk events.•Explicates health professionals’ mental models of Twitter for risk communication.•Operationalises the Social ...Amplification of Risk Framework using system dynamics.•Captures non-linear, complex dynamics of trust via a causal loop diagram.•Health organisations face challenges institutionalising the use of Twitter.
Communication of health risk events is a complex and challenging task. The advent of information and communication technology along with the following popularisation and widespread uptake of social media are reshaping the field of risk communication. Guided by key tenets of the Social Amplification of Risk Framework, this study developed a causal loop diagram, capturing the perceptions of professionals in health organisations regarding the role of Twitter during risk events. The aim of this paper is to explore the use of the causal loop diagram and its role with rationalising the use of Twitter in risk communication strategies. A key finding of the model is the central role of trust and its interrelationship with other factors during a risk event. A contribution is made to operational research through the novel use of soft system dynamics in risk communication, to risk communication through the investigation of the new medium Twitter and also to research on the Social Amplification of Risk Framework by providing a means through which to operationalise the framework.
There are concerns that reefs will transition from net calcifying to net dissolving in the near future due to decreasing calcification and increasing dissolution rates. Here, we present in situ rates ...of net ecosystem calcification (NEC) and net ecosystem production (NEP) on a coral reef flat using a slack‐water approach. Up until dusk, the reef was net calcifying in most months but shifted to net dissolution in austral summer, coinciding with high respiration rates and a lower aragonite saturation state (Ωarag). The estimated sediment contribution to NEC ranged from 8% to 21% during the day and 45% to 78% at night, indicating that high rates of sediment dissolution may cause the transition to reef dissolution. This late afternoon seasonal transition to negative NEC may be an early warning sign of the reef shifting to a net dissolving state and may be occurring on other reefs.
Plain Language Summary
Positive rates of net ecosystem calcification and net ecosystem production are regarded as fundamental to the healthy functioning of coral reef ecosystems. In particular, positive ecosystem calcification is required to maintain the structural complexity that sustains many of the ecosystem functions of coral reefs. While most reefs are currently net calcifying, there is growing concern that increased pressures from rising sea surface temperatures and reductions in ocean surface pH (ocean acidification OA) will both depress coral calcification and increase dissolution. This could result in a shift of the whole ecosystem closer to a state of net dissolution before the end of the century. Here, we measured hourly afternoon rates of net ecosystem calcification and production on a coral reef flat over 10 months of the year. We found that the reef flat was already showing signs of net dissolution during certain times of the year (austral summer), which may become more extreme under global climate change. These temporary shifts in coral reef metabolism may provide insight into how the ecosystem will respond to future, more persistent periods of net dissolution driven by OA.
Key Points
Ecosystem calcification and sediment calcification on Heron Island reef exceed dissolution such that net ecosystem calcification (NEC) remains largely positive
Shallow, calcium carbonate sediments contribute 8%–12% of reef NEC during the day and at least 45%–78% of reef NEC at night
The seasonal shifts to negative net ecosystem calcification before dusk may be a precursor of periodic net ecosystem dissolution
Turf algal assemblages are ubiquitous primary producers on coral reefs, but little is known about the response of this diverse group to ocean acidification (OA) across different temperatures. We ...tested the hypothesis that CO
2
influences the functional response of epilithic and endolithic turf assemblages to increasing temperature. Replicate carbonate plugs covered by turf were collected from the reef and exposed to ambient and high
p
CO
2
(1000 µatm) conditions for 3 weeks. Each
p
CO
2
treatment was replicated across six temperatures (24.0–31.5 °C) that spanned the full seasonal temperature range on a fringing reef in Moorea, French Polynesia, and included one warming treatment (3 °C above daily average temperatures). Temperature and CO
2
enrichment had complex, and sometimes interactive, effects on turf metabolism and growth. Photosynthetic and respiration rates were enhanced by increasing temperature, with an interactive effect of CO
2
enrichment. Photosynthetic rates were amplified by high CO
2
in the warmest temperatures, while the increase in respiration rates with temperature were enhanced under ambient CO
2
. Epilithic turf growth rates were not affected by temperature, but increased in response to CO
2
enrichment. We found that CO
2
and temperature interactively affected the endolithic assemblage, with the highest growth rates under CO
2
enrichment, but only at the warmest temperatures. These results demonstrate how OA may influence algal physiology and growth across a range of ecologically relevant temperatures, and indicate that the effects of CO
2
enrichment on coral-reef turf assemblages can be temperature dependent. The complex effects of CO
2
enrichment and temperature across a suite of algal responses illustrates the importance of incorporating multiple stressors into global change experiments.
Studies of coral colonies show that ocean acidification and temperature can affect calcification; however, less is known about the consequences for their populations. Understanding intraspecific ...variation in the response of corals to these conditions will be important for evaluating population-level consequences of environmental change. We examined intraspecific variability in the effects of elevated temperature and carbon dioxide levels on net calcification (
G
n
) in the coral
Acropora pulchra
in Moorea, French Polynesia. A common garden experiment showed that
G
n
in four colonies was affected negatively by high partial pressure of CO
2
(pCO
2
) (~1000 μatm cf. ~400 μatm ambient conditions), whereas elevated temperature (30 °C cf. 27 °C) had a negative effect on one colony. Together, these results reveal intraspecific variation in the response of
G
n
to temperature but not to pCO
2
. The fastest growing colonies under ambient temperature and ambient pCO
2
showed the greatest decline in
G
n
at high temperature and elevated pCO
2
. For reef corals, effects of temperature and pCO
2
on calcification that depend on the intrinsic growth rate have potentially important consequences, because they imply that coral colonies contributing the most to population-level calcification will be disproportionately affected by changing environmental conditions.
A key challenge of functional genomics today is to generate well-annotated data sets that can be interpreted across different platforms and technologies. Large-scale functional genomics data often ...fail to connect to standard experimental approaches of gene characterization in individual laboratories. Furthermore, a lack of universal annotation standards for phenotypic data sets makes it difficult to compare different screening approaches. Here we address this problem in a screen designed to identify all genes required for the first two rounds of cell division in the Caenorhabditis elegans embryo. We used RNA-mediated interference to target 98% of all genes predicted in the C. elegans genome in combination with differential interference contrast time-lapse microscopy. Through systematic annotation of the resulting movies, we developed a phenotypic profiling system, which shows high correlation with cellular processes and biochemical pathways, thus enabling us to predict new functions for previously uncharacterized genes.
Coral bleaching has impacted reefs worldwide and the predictions of near-annual bleaching from over two decades ago have now been realized. While technology currently provides the means to predict ...large-scale bleaching, predicting reef-scale and within-reef patterns in real-time for all reef users is limited. In 2020, heat stress across the Great Barrier Reef underpinned the region's third bleaching event in 5 years. Here we review the heterogeneous emergence of bleaching across Heron Island reef habitats and discuss the oceanographic drivers that underpinned variable bleaching emergence. We do so as a case study to highlight how reef end-user groups who engage with coral reefs in different ways require targeted guidance for how, and when, to alter their use of coral reefs in response to bleaching events. Our case study of coral bleaching emergence demonstrates how within-reef scale nowcasting of coral bleaching could aid the development of accessible and equitable bleaching response strategies on coral reefs. Also see the video abstract here: https://youtu.be/N9Tgb8N-vN0.
Global warming (and the consequent increase in sea surface temperature) is expected to modify rates of gross primary production (GPP), respiration (
R
), and net calcium carbonate (CaCO
3
) ...dissolution in permeable coral reef carbonate sediments. Previous simulations of seawater warming on coral reef sediments found a decline in the GPP/
R
ratio and an associated increase in CaCO
3
dissolution but were only conducted over a short timescale (< 24 h). To date, no studies have examined the prolonged (> 24 h) effect of seawater warming on coral reef CaCO
3
sediment metabolism and dissolution, which may allow the benthic community to acclimatise. This study used 600-L flume aquaria to examine the effect of seawater warming on GPP,
R
, and CaCO
3
dissolution in the permeable coral reef CaCO
3
sediments of Mo’orea, French Polynesia, over a period of 15 d. On average, when exposed to warmed seawater (+ 2.8 °C),
R
in the CaCO
3
sediments was enhanced (+ 58%) to a greater extent than GPP (+19%), resulting in a decline in GPP/
R
(− 23%) and an associated increase in net CaCO
3
dissolution (+ 126%). The magnitude of these warming-mediated metabolic changes increased each day until reaching a plateau after about 8 d, indicating that 24-h experiments may be underestimating the effect of warming over longer timescales. Interestingly, the increase in dissolution relative to control treatments was more striking during the day (+ 163%) than at night (+ 89%), suggesting that warming acted to both enhance geochemical dissolution and reduce biogenic calcification or inorganic precipitation. Together, these data indicate that, over the timescale observed here, photosynthesis and associated inorganic and biogenic CaCO
3
precipitation do not exhibit the ability to counterbalance the warming-mediated increase in sediment heterotrophy and CaCO
3
dissolution.
Rituximab was the first chemotherapeutic monoclonal antibody (CmAb) approved for clinical use in cancer therapeutics in 1997 and has significantly improved the clinical outcomes in non-Hodgkin's ...lymphoma. Since then, numerous CmAbs have been developed and approved for the treatment of various haematologic and solid human cancers. In this review, the classification, efficacy and significantly reduced toxicity of CmAbs available for use in the United States of America are presented. Finally, the limitations of CmAbs and future considerations are explored.
Maladaptive cognitive biases such as negative attributional style and hopelessness have been implicated in the development and maintenance of depression. According to the hopelessness theory of ...depression, hopelessness mediates the association between attributional style and depression. The aetiological processes underpinning this influential theory remain unknown. The current study investigated genetic and environmental influences on hopelessness and its concurrent and longitudinal associations with attributional style and depression across adolescence and emerging adulthood. Furthermore, given high co-morbidity between depression and anxiety, the study investigated whether these maladaptive cognitions constitute transdiagnostic cognitive content common to both internalizing symptoms.
A total of 2619 twins/siblings reported attributional style (mean age 15 and 17 years), hopelessness (mean age 17 years), and depression and anxiety symptoms (mean age 17 and 20 years).
Partial correlations revealed that attributional style and hopelessness were uniquely associated with depression but not anxiety symptoms. Hopelessness partially mediated the relationship between attributional style and depression. Hopelessness was moderately heritable (A = 0.37, 95% confidence interval 0.28-0.47), with remaining variance accounted for by non-shared environmental influences. Independent pathway models indicated that a set of common genetic influences largely accounted for the association between attributional style, hopelessness and depression symptoms, both concurrently and across development.
The results provide novel evidence that associations between attributional style, hopelessness and depression symptoms are largely due to shared genetic liability, suggesting developmentally stable biological pathways underpinning the hopelessness theory of depression. Both attributional style and hopelessness constituted unique cognitive content in depression. The results inform molecular genetics research and cognitive treatment approaches.
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