Percorrer por autor "Rogers, Alice"
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- Deep reefs of the Great Barrier Reef offer limited thermal refuge during mass coral bleachingPublication . Rodrigues Frade, Pedro; Bongaerts, Pim; Englebert, Norbert; Rogers, Alice; Gonzalez-Rivero, Manuel; Hoegh-Guldberg, OveOur rapidly warming climate is threatening coral reefs as thermal anomalies trigger mass coral bleaching events. Deep (or "mesophotic") coral reefs are hypothesised to act as major ecological refuges from mass bleaching, but empirical assessments are limited. We evaluated the potential of mesophotic reefs within the Great Barrier Reef (GBR) and adjacent Coral Sea to act as thermal refuges by characterising long-term temperature conditions and assessing impacts during the 2016 mass bleaching event. We found that summer upwelling initially provided thermal relief at upper mesophotic depths (40 m), but then subsided resulting in anomalously warm temperatures even at depth. Bleaching impacts on the deep reefs were severe (40% bleached and 6% dead colonies at 40 m) but significantly lower than at shallower depths (60-69% bleached and 8-12% dead at 5-25 m). While we confirm that deep reefs can offer refuge from thermal stress, we highlight important caveats in terms of the transient nature of the protection and their limited ability to provide broad ecological refuge.
- Exposure of an intertidal fish to simulated heatwaves and suspended sediment – a multistressor approachPublication . Resende, Anna Carolina; Vinagre, Catarina; Rogers, AliceExtreme climatic events, such as marine heatwaves (MHW) and increased suspended sediment concentration (SSC), are increasing in frequency and intensity, resulting in sudden changes to coastal environments, especially intertidal zones. Intertidal animals experience conditions that substantially fluctuate over temporal and spatial scales and therefore require the ability to physiologically tolerate these fluctuations. Since multiple stressors often co-occur and natural populations tend to respond to local environmental fluctuations, we aimed to investigate individual and combined effects of MHW and increased suspended sedimentation in Forsterygion lapillum from two neighbouring coastal areas with distinct water temperatures and wave current regimes by assessing fish oxygen consumption rate, mortality and weight loss. Results showed that in both F. lapillum populations, oxygen consumption rate and survival probability were unaffected by any treatment. However, fish from both populations lost weight during heatwave and multistressor treatments (i.e. heatwave and sedimentation), while fish from the sedimentation treatment alone did not lose weight. Although a direct effect on fish respiration was not found, our results indicate that F. lapillum performance is reduced when exposed to heatwaves individually and in combination with increased sediment suspension. Weight loss indicates that fish experiencing these stressors were unable to meet their metabolic demands.
- Short‐term performance responses of an intertidal fish to sedimentation and warmingPublication . Resende, Anna Carolina; Campbell, Lucy; Vinagre, Catarina; Rogers, AliceClimate change is altering coastal ecosystems by causing environmental fluctuations, such as increases in temperature and turbidity, which pose major implications for fish physiology and behaviour. Increases in temperature affect fish food intake, swimming capacity and oxygen delivery, while increases in turbidity can impair or enhance prey detection, as well as affect fish movement. Since these stressors often act together, understanding their combined effects is critical. We investigated how short-term increases in temperature and turbidity, both separately and in combination, influenced the foraging and swimming performance of the common triplefin, Forsterygion lapillum Hardy 1989, and measured oxygen consumption during acute thermal ramping to explore links between thermal tolerance and performance. Results show that F. lapillum strike speed was slower in high turbidity treatments, indicating that F. lapillum relies on visual cues to feed, and consequently, fish foraging performance is impaired in sedimented waters. Moreover, fish routine swimming speed and burst speed were unaffected by any treatment, suggesting that F. lapillum can adapt its swimming performance to the increases in temperature and turbidity that were tested. During acute thermal ramping, fish oxygen consumption rate was found to increase only at temperatures above 24 C. This can explain F. lapillum's lack of adjustment in swimming speed, burst speed and strike speed to increases in temperature during the experiment and suggests that oxygen delivery starts to be compromised at temperatures above this threshold. Our findings highlight F. lapillum resilience to moderate temperature increases but reveal vulnerability to increased sedimentation due to reduced foraging efficiency.