Short-term ocean acidification decreases pulsation and growth of the widespread soft coral Xenia umbellata.

Coral reefs may experience lower pH values as a result of ocean acidification (OA), which has negative consequences, particularly for calcifying organisms. Thus far, the effects of this global factor have been mainly investigated on hard corals, while the effects on soft corals remain relatively understudied. We therefore carried out a manipulative aquarium experiment for 21 days to study the response of the widespread pulsating soft coral Xenia umbellata to simulated OA conditions. We gradually decreased the pH from ambient (~8.3) to three consecutive 7-day long pH treatments of 8.0, 7.8, and 7.6, using a CO2 dosing system. Monitored response variables included pulsation rate, specific growth rate, visual coloration, survival, Symbiodiniaceae cell densities and chlorophyll a content, photosynthesis and respiration, and finally stable isotopes of carbon (C) and nitrogen (N) as well as CN content. Pulsation decreased compared to controls with each consecutive lowering of the pH, i.e., 17% at pH 8.0, 26% at pH 7.8 and 32% at pH 7.6, accompanied by an initial decrease in growth rates of ~60% at pH 8.0, not decreasing further at lower pH. An 8.3 ‰ decrease of δ13C confirmed that OA exposed colonies had a higher uptake and availability of atmospheric CO2. Coral productivity, i.e., photosynthesis, was not affected by higher dissolved inorganic C availability and none of the remaining response variables showed any significant differences. Our findings suggest that pulsation is a phenotypically plastic mechanism for X. umbellata to adjust to different pH values, resulting in reduced growth rates only, while maintaining high productivity. Consequently, pulsation may allow X. umbellata to inhabit a broad pH range with minimal effects on its overall health. This resilience may contribute to the competitive advantage that soft corals, particularly X. umbellata, have over hard corals.

Construct validity, test-retest reliability, and the ability to detect change of the Canadian Occupational Performance Measure in a spinal cord injury population.

Study design: Cross-sectional study. Objectives: To examine the construct validity and the ability to detect change, of the Italian version of the Canadian Occupational Performance Measure (COPM) in a spinal cord injury (SCI) population. Settings: Rehabilitation service of the Paraplegic Center of Ostia, Italy. Methods: Thirty-nine spinal cord injury participants were recruited. The clinimetric properties of the measure were assessed following international guidelines. Cronbach's alpha and the intraclass correlation coefficient were assessed for internal consistency and test-retest reliability, respectively. Construct validity was evaluated, by calculating correlation between COPM and the Spinal Cord Independence Measure (SCIM) through Pearson's correlation coefficient and Spearman's Rho. The ability to detect change was evaluated on the overall sample. Results: The COPM was shown to be reliable in a spinal cord injury sample with positive and statistically significant results for Cronbach's alpha (0.89) and ICC (0.99 for the performance subtest and 0.98 for the satisfaction subtest). Correlation coefficients did not show a correlation between the COPM total score and the SCIM. The COPM scores improved significantly during in-patient rehabilitation, moreover the mean change between the start of treatment and the end of the therapy as evaluated with the Wilcoxon signed-rank test was -4.25 points for the performance score and -2.96 points for the satisfaction score. Conclusions: This study showed that the COPM is a reliable tool for assessing SCI clients' perceived performance of daily activities and their satisfaction with their performance.