ABSTRACT
Coral energy and nutrient acquisition strategies are complex and sensitive to environmental conditions such as water flow. While high water flow can enhance feeding in hard corals, knowledge about the effects of water flow on the feeding of soft corals, particularly those pulsating, is still limited. In this study, we thus investigated the effects of feeding and water flow on the physiology of the pulsating soft coral Xenia umbellata. We crossed three feeding treatments: (i) no feeding, (ii) particulate organic matter (POM) in the form of phytoplankton and (iii) dissolved organic carbon (DOC) in the form of glucose, with four water volume exchange rates (200, 350, 500 and 650 L h-1) over 15 days. Various ecophysiological parameters were assessed including pulsation rate, growth rate, isotopic and elemental ratios of carbon (C) and nitrogen (N) as well as photo-physiological parameters of the Symbiodiniaceae (cell density, chlorophyll-a and mitotic index). Water flow had no significant effect but feeding had a substantial impact on the physiology of the X. umbellata holobiont. In the absence of food, corals exhibited significantly lower pulsation rates, lower Symbiodiniaceae cell density and lower mitotic indices compared to the fed treatments, yet significantly higher chlorophyll-a per cell and total N content. Differences were also observed between the two feeding treatments, with significantly higher pulsation rates and lower chlorophyll-a per cell in the DOC treatment, but higher C and N content in the POM treatment. Our findings suggest that the X. umbellata holobiont can be viable under different trophic strategies, though favouring mixotrophy. Additionally, the physiology of the X. umbellata may be regulated through its own pulsating behaviour without any positive or negative effects from different water flow. Therefore, this study contributes to our understanding of soft coral ecology, particularly regarding the competitive success and widespread distribution of X. umbellata.
ABSTRACT
OBJECTIVES: The COVID-19 pandemic significantly impacted mental health, health-related behaviours such as drinking and illicit drug use and the accessibility of health and social care services. How these pandemic shocks affected 'despair'-related mortality in different countries is less clear. This study uses public data to compare deaths from alcohol, drugs and suicide in the United States and the United Kingdom to identify similarities or differences in the impact of the pandemic on important non-COVID causes of death across countries and to consider the public health implications of these trends. STUDY DESIGN AND METHODS: Data were taken from publicly available mortality figures for England and Wales, Northern Ireland, Scotland and the United States of America, 2001-2021, and analysed descriptively through age-standardised and age-specific mortality rates from suicide, alcohol and drug use. RESULTS: Alcohol-specific deaths increased in all countries between 2019 and 2021, most notably in the United States and, to a lesser extent, England and Wales. Suicide rates did not increase markedly during the pandemic in any of the included nations. Drug-related mortality rates rose dramatically over the same period in the United States but not in other nations. CONCLUSIONS: Mortality from 'deaths of despair' during the pandemic has displayed divergent trends between causes and countries. Concerns about increases in deaths by suicide appear to have been unfounded, whereas deaths due to alcohol have risen across the United Kingdom and in the United States and across almost all age groups. Scotland and the United States had similarly high levels of drug-related deaths pre-pandemic, but the differing trends during the pandemic highlight the different underlying causes of these drug death epidemics and the importance of tailoring policy responses to these specific contexts.
